Textonyms

When entering text on a phone's digital pad it is possible that a particular combination of digits corresponds to more than one word. Such are called textonyms.

Assuming the digit keys are mapped to letters as follows:

    2 -> ABC
    3 -> DEF
    4 -> GHI
    5 -> JKL
    6 -> MNO
    7 -> PQRS
    8 -> TUV
    9 -> WXYZ

Task

Write a program that finds textonyms in a list of words such as Textonyms/wordlist or unixdict.txt.

The task should produce a report:

There are #{0} words in #{1} which can be represented by the digit key mapping.
They require #{2} digit combinations to represent them.
#{3} digit combinations represent Textonyms.

Where:

#{0} is the number of words in the list which can be represented by the digit key mapping.
#{1} is the URL of the wordlist being used.
#{2} is the number of digit combinations required to represent the words in #{0}.
#{3} is the number of #{2} which represent more than one word.

At your discretion show a couple of examples of your solution displaying Textonyms.

E.G.:

 2748424767 -> "Briticisms", "criticisms"

Extra credit

Use a word list and keypad mapping other than English.

Other tasks related to string operations:

Metrics

Counting

Remove/replace

Anagrams/Derangements/shuffling

Find/Search/Determine

Formatting

Song lyrics/poems/Mad Libs/phrases

Tokenize

Sequences

11l

Translation of: Python

[Char = String] CH2NUM
L(chars) ‘abc def ghi jkl mno pqrs tuv wxyz’.split(‘ ’)
   V num = L.index + 2
   L(ch) chars
      CH2NUM[ch] = String(num)

F mapnum2words(words)
   DefaultDict[String, [String]] number2words
   V reject = 0
   L(word) words
      X.try
         number2words[word.map(ch -> :CH2NUM[ch]).join(‘’)].append(word)
      X.catch KeyError
         reject++
   R (number2words, reject)

V words = File(‘unixdict.txt’).read().rtrim("\n").split("\n")
print(‘Read #. words from 'unixdict.txt'’.format(words.len))
V wordset = Set(words)
V (num2words, reject) = mapnum2words(words)

F interactiveconversions()
   L(inp) (‘rosetta’, ‘code’, ‘2468’, ‘3579’)
      print("\nType a number or a word to get the translation and textonyms: "inp)
      I all(inp.map(ch -> ch C ‘23456789’))
         I inp C :num2words
            print(‘  Number #. has the following textonyms in the dictionary: #.’.format(inp, (:num2words[inp]).join(‘, ’)))
         E
            print(‘  Number #. has no textonyms in the dictionary.’.format(inp))
      E I all(inp.map(ch -> ch C :CH2NUM))
         V num = inp.map(ch -> :CH2NUM[ch]).join(‘’)
         print(‘  Word #. is#. in the dictionary and is number #. with textonyms: #.’.format(inp, (I inp C :wordset {‘’} E ‘n't’), num, (:num2words[num]).join(‘, ’)))
      E
         print(‘  I don't understand '#.'’.format(inp))

V morethan1word = sum(num2words.keys().filter(w -> :num2words[w].len > 1).map(w -> 1))
V maxwordpernum = max(num2words.values().map(values -> values.len))
print(‘
There are #. words in #. which can be represented by the Textonyms mapping.
They require #. digit combinations to represent them.
#. digit combinations represent Textonyms.’.format(words.len - reject, ‘'unixdict.txt'’, num2words.len, morethan1word))

print("\nThe numbers mapping to the most words map to #. words each:".format(maxwordpernum))
V maxwpn = sorted(num2words.filter((key, val) -> val.len == :maxwordpernum))
L(num, wrds) maxwpn
   print(‘  #. maps to: #.’.format(num, wrds.join(‘, ’)))

interactiveconversions()

Output:

Read 25104 words from 'unixdict.txt'

There are 24978 words in 'unixdict.txt' which can be represented by the Textonyms mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

The numbers mapping to the most words map to 9 words each:
  269 maps to: amy, any, bmw, bow, box, boy, cow, cox, coy
  729 maps to: paw, pax, pay, paz, raw, ray, saw, sax, say

Type a number or a word to get the translation and textonyms: rosetta
  Word rosetta is in the dictionary and is number 7673882 with textonyms: rosetta

Type a number or a word to get the translation and textonyms: code
  Word code is in the dictionary and is number 2633 with textonyms: bode, code, coed

Type a number or a word to get the translation and textonyms: 2468
  Number 2468 has the following textonyms in the dictionary: ainu, chou

Type a number or a word to get the translation and textonyms: 3579
  Number 3579 has no textonyms in the dictionary.

ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.3.win32

Uses the Algol 68G specific "to upper" procedure.

The associative array MODEs, operators etc. are contained in:

File: aArray.a68 on Rosetta Code at ALGOL 68/prelude#aArray.a68
File: aArrayBase.a68 on Rosetta Code at ALGOL 68/prelude#aArrayBase.a68

# find textonyms in a list of words #
# use the associative array in the Associate array/iteration task     #
PR read "aArray.a68" PR

# returns the number of occurances of ch in text #
PROC count = ( STRING text, CHAR ch )INT:
     BEGIN
         INT result := 0;
         FOR c FROM LWB text TO UPB text DO IF text[ c ] = ch THEN result +:= 1 FI OD;
         result
     END # count # ;

CHAR invalid char = "*";

# returns text with the characters replaced by their text digits      #
PROC to text = ( STRING text )STRING:
     BEGIN
         STRING result := text;
         FOR pos FROM LWB result TO UPB result DO
             CHAR c = to upper( result[ pos ] );
             IF   c = "A" OR c = "B" OR c = "C"            THEN result[ pos ] := "2"
             ELIF c = "D" OR c = "E" OR c = "F"            THEN result[ pos ] := "3"
             ELIF c = "G" OR c = "H" OR c = "I"            THEN result[ pos ] := "4"
             ELIF c = "J" OR c = "K" OR c = "L"            THEN result[ pos ] := "5"
             ELIF c = "M" OR c = "N" OR c = "O"            THEN result[ pos ] := "6"
             ELIF c = "P" OR c = "Q" OR c = "R" OR c = "S" THEN result[ pos ] := "7"
             ELIF c = "T" OR c = "U" OR c = "V"            THEN result[ pos ] := "8"
             ELIF c = "W" OR c = "X" OR c = "Y" OR c = "Z" THEN result[ pos ] := "9"
             ELSE # not a character that can be encoded #       result[ pos ] := invalid char
             FI
         OD;
         result
     END # to text # ;

# read the list of words and store in an associative array           #

CHAR separator = "/"; # character that will separate the textonyms   #

IF  FILE input file;
    STRING file name = "unixdict.txt";
    open( input file, file name, stand in channel ) /= 0
THEN
    # failed to open the file #
    print( (  "Unable to open """ + file name + """", newline ) )
ELSE
    # file opened OK #
    BOOL at eof := FALSE;
    # set the EOF handler for the file #
    on logical file end( input file, ( REF FILE f )BOOL:
                                     BEGIN
                                         # note that we reached EOF on the #
                                         # latest read #
                                         at eof := TRUE;
                                         # return TRUE so processing can continue #
                                         TRUE
                                     END
                       );
    REF AARRAY words   := INIT LOC AARRAY;
    INT word count     := 0;
    INT combinations   := 0;
    INT multiple count := 0;
    INT max length     := 0;
    WHILE STRING word;
          get( input file, ( word, newline ) );
          NOT at eof
    DO
        STRING text word = to text( word );
        IF count( text word, invalid char ) = 0 THEN
            # the word can be fully encoded #
            word count +:= 1;
            INT length := ( UPB word - LWB word ) + 1;
            IF length > max length THEN
                # this word is longer than the maximum length found so far #
                max length := length
            FI; 
            IF ( words // text word ) = "" THEN
                # first occurance of this encoding #
                combinations +:= 1;
                words // text word := word
            ELSE
                # this encoding has already been used #
                IF count( words // text word, separator ) = 0
                THEN
                    # this is the second time this encoding is used #
                    multiple count +:= 1
                FI;
                words // text word +:= separator + word
            FI
        FI
    OD;
    # close the file #
    close( input file );

    # find the maximum number of textonyms #

    INT max textonyms := 0;

    REF AAELEMENT e := FIRST words;
    WHILE e ISNT nil element DO
        INT textonyms := count( value OF e, separator );
        IF  textonyms > max textonyms 
        THEN
            max textonyms := textonyms
        FI;
        e := NEXT words
    OD;

    print( ( "There are ", whole( word count, 0 ), " words in ", file name, " which can be represented by the digit key mapping.", newline ) );
    print( ( "They require ", whole( combinations, 0 ), " digit combinations to represent them.", newline ) );
    print( ( whole( multiple count, 0 ), " combinations represent Textonyms.", newline ) );
 
    # show the textonyms with the maximum number #
    print( ( "The maximum number of textonyms for a particular digit key mapping is ", whole( max textonyms + 1, 0 ), " as follows:", newline ) ); 
    e := FIRST words;
    WHILE e ISNT nil element DO
        IF  INT textonyms := count( value OF e, separator );
            textonyms = max textonyms 
        THEN
            print( ( "    ", key OF e, " encodes ", value OF e, newline ) )
        FI;
        e := NEXT words
    OD;

    # show the textonyms with the maximum length #
    print( ( "The longest words are ", whole( max length, 0 ), " chracters long", newline ) );
    print( ( "Encodings with this length are:", newline ) );
    e := FIRST words;
    WHILE e ISNT nil element DO
        IF max length = ( UPB key OF e - LWB key OF e ) + 1
        THEN
            print( ( "    ", key OF e, " encodes ", value OF e, newline ) )
        FI;
        e := NEXT words
    OD;

FI

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 combinations represent Textonyms.
The maximum number of textonyms for a particular digit key mapping is 9 as follows:
    269 encodes amy/any/bmw/bow/box/boy/cow/cox/coy
    729 encodes paw/pax/pay/paz/raw/ray/saw/sax/say
The longest words are 22 chracters long
Encodings with this length are:
    3532876362374256472749 encodes electroencephalography

AppleScript

Vanilla

use AppleScript version "2.3.1" -- OS X 10.9 (Mavericks) or later.
-- https://rosettacode.org/wiki/Sorting_algorithms/Quicksort#Straightforward
use sorter : script "Quicksort"
use scripting additions

on textonyms(posixPath, query)
    set digits to "23456789"
    set keys to {"", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"}
    set {mv, LF} to {missing value, linefeed}
    -- Check input.
    try
        set reporting to (query's class is not text)
        if (not reporting) then
            repeat with chr in query
                if (chr is not in digits) then error "Invalid digit input"
            end repeat
            set digitCount to (count query)
        end if
        script o
            property |words| : (do shell script ("cat " & posixPath))'s paragraphs
            property combos : mv
        end script
    on error errMsg
        display alert "Textonyms handler: parameter error" message ¬
            errMsg as critical buttons {"Stop"} default button 1
        error number -128
    end try
    
    ignoring case
        -- Lose obvious no-hope words.
        set alphabet to join(keys's rest, "")
        repeat with i from 1 to (count o's |words|)
            set wrd to o's |words|'s item i
            if ((reporting) or (wrd's length = digitCount)) then
                repeat with chr in wrd
                    if (chr is not in alphabet) then
                        set o's |words|'s item i to mv
                        exit repeat
                    end if
                end repeat
            else
                set o's |words|'s item i to mv
            end if
        end repeat
        set o's |words| to o's |words|'s every text
        set wordCount to (count o's |words|)
        
        -- Derive digit combinations from the rest.
        set txt to join(o's |words|, LF)
        repeat with d in digits
            set d to d's contents
            repeat with letter in keys's item d
                set txt to replaceText(txt, letter's contents, d)
            end repeat
        end repeat
        set o's combos to txt's paragraphs
    end ignoring
    
    -- Return the appropriate result
    considering case -- Case insensitivity not needed with digits.
        if (reporting) then
            tell sorter to sort(o's combos, 1, wordCount)
            set {previousCombo, comboCount, textonymCount, counting} to ¬
                {"", wordCount, 0, true}
            repeat with i from 1 to wordCount
                set thisCombo to o's combos's item i
                if (thisCombo = previousCombo) then
                    set comboCount to comboCount - 1
                    if (counting) then
                        set textonymCount to textonymCount + 1
                        set counting to false
                    end if
                else
                    set previousCombo to thisCombo
                    set counting to true
                end if
            end repeat
            set output to (wordCount as text) & " words in '" & ¬
                (do shell script ("basename " & posixPath)) & ¬
                "' can be represented by the digit key mapping." & ¬
                (LF & comboCount & " digit combinations are required to represent them.") & ¬
                (LF & textonymCount & " of the digit combinations represent Textonyms.")
        else
            set output to {}
            repeat with i from 1 to wordCount
                if (o's combos's item i = query) then set output's end to o's |words|'s item i
            end repeat
            if ((count output) = 1) then set output to {}
        end if
    end considering
    
    return output
end textonyms

on join(lst, delim)
    set astid to AppleScript's text item delimiters
    set AppleScript's text item delimiters to delim
    set txt to lst as text
    set AppleScript's text item delimiters to astid
    return txt
end join

on replaceText(mainText, searchText, replacementText)
    set astid to AppleScript's text item delimiters
    set AppleScript's text item delimiters to searchText
    set textItems to mainText's text items
    set AppleScript's text item delimiters to replacementText
    set mainText to textItems as text
    set AppleScript's text item delimiters to astid
    return mainText
end replaceText

on task()
    set posixPath to "~/Desktop/www.rosettacode.org/unixdict.txt"
    set report to textonyms(posixPath, missing value)
    set output to {report, "", "Examples:"}
    repeat with digitCombo in {"729", "723353", "25287876746242"}
        set foundWords to textonyms(posixPath, digitCombo's contents)
        set output's end to digitCombo & " --> {" & join(foundWords, ", ") & "}"
    end repeat
    return join(output, linefeed)
end task

task()

Output:

"24978 words in 'unixdict.txt' can be represented by the digit key mapping.
22903 digit combinations are required to represent them.
1473 of the digit combinations represent Textonyms.

Examples:
729 --> {paw, pax, pay, paz, raw, ray, saw, sax, say}
723353 --> {paddle, raffle, saddle}
25287876746242 --> {claustrophobia, claustrophobic}"

AppleScriptObjC

use AppleScript version "2.4" -- OS X 10.10 (Yosemite) or later
use framework "Foundation"
use scripting additions

on textonyms(posixPath, query)
    set digits to "23456789"
    set keys to {"", "[abc]", "[def]", "[ghi]", "[jkl]", "[mno]", "[pqrs]", "[tuv]", "[wxyz]"}
    set {mv, LF} to {missing value, linefeed}
    -- Check input.
    try
        set reporting to (query's class is not text)
        if (not reporting) then
            repeat with chr in query
                if (chr is not in digits) then error "Invalid digit input"
            end repeat
            set digitCount to (count query)
        end if
        set || to current application
        set pathStr to (||'s NSString's stringWithString:(posixPath))'s ¬
            stringByExpandingTildeInPath()
        set {txt, err} to ||'s NSMutableString's stringWithContentsOfFile:(pathStr) ¬
            usedEncoding:(mv) |error|:(reference)
        if (err ≠ mv) then error (err's localizedDescription() as text)
    on error errMsg
        display alert "Textonyms handler: parameter error" message ¬
            errMsg as critical buttons {"Stop"} default button 1
        error number -128
    end try
    
    -- Lose obvious no-hope words.
    set regex to ||'s NSRegularExpressionSearch
    txt's replaceOccurrencesOfString:("\\R") withString:(LF) ¬
        options:(regex) range:({0, txt's |length|()})
    set |words| to txt's componentsSeparatedByString:(LF)
    if ((reporting) or (digitCount > 9)) then
        set predFormat to "(self MATCHES '(?i)[a-z]++')"
    else
        set predFormat to "(self MATCHES '(?i)[a-z]{" & digitCount & "}+')"
    end if
    set predicate to ||'s NSPredicate's predicateWithFormat:(predFormat)
    set |words| to |words|'s filteredArrayUsingPredicate:(predicate)
    set wordCount to |words|'s |count|()
    
    -- Derive digit combinations from the rest.
    set txt to (|words|'s componentsJoinedByString:(LF))'s mutableCopy()
    set range to {0, txt's |length|()}
    repeat with d in digits
        (txt's replaceOccurrencesOfString:("(?i)" & keys's item d) withString:(d) ¬
            options:(regex) range:(range))
    end repeat
    set combos to txt's componentsSeparatedByString:(LF)
    
    -- Return the appropriate result.
    if (reporting) then
        set comboSet to ||'s NSSet's setWithArray:(combos)
        set comboCount to comboSet's |count|()
        set textonymSet to ||'s NSCountedSet's alloc()'s initWithArray:(combos)
        textonymSet's minusSet:(comboSet)
        set textonymCount to textonymSet's |count|()
        set output to (wordCount as text) & " words in '" & ¬
            (pathStr's lastPathComponent()) & ¬
            "' can be represented by the digit key mapping." & ¬
            (LF & comboCount & " digit combinations are required to represent them.") & ¬
            (LF & textonymCount & " of the digit combinations represent Textonyms.")
    else
        set output to {}
        set range to {0, wordCount}
        set i to combos's indexOfObject:(query) inRange:(range)
        repeat until (i > wordCount)
            set output's end to (|words|'s objectAtIndex:(i)) as text
            set range to {i + 1, wordCount - (i + 1)}
            set i to combos's indexOfObject:(query) inRange:(range)
        end repeat
        if ((count output) = 1) then set output to {}
    end if
    
    return output
end textonyms

on join(lst, delim)
    set astid to AppleScript's text item delimiters
    set AppleScript's text item delimiters to delim
    set txt to lst as text
    set AppleScript's text item delimiters to astid
    return txt
end join

on task()
    set posixPath to "~/Desktop/www.rosettacode.org/unixdict.txt"
    set report to textonyms(posixPath, missing value)
    set output to {report, "", "Examples:"}
    repeat with digitCombo in {"729", "723353", "25287876746242"}
        set foundWords to textonyms(posixPath, digitCombo's contents)
        set output's end to digitCombo & " --> {" & join(foundWords, ", ") & "}"
    end repeat
    return join(output, linefeed)
end task

task()

Output:

Same as for the "vanilla" solution.

Arturo

words: read.lines relative "unixdict.txt" | select => [match? & {/^[a-z]+$/}]

nums: "22233344455566677778889999"

phone: $ => [
    join map &'c -> nums\[sub to :integer c 97]
]

textonyms: #[]
tcount: 0

loop words 'w [
    p: phone w
    if? key? textonyms p [
        textonyms\[p]: textonyms\[p] ++ w
        if 2 = size textonyms\[p] -> 'tcount + 1
    ]
    else -> textonyms\[p]: @[w]
]

print ~{
    There are |size words| words in unixdict.txt which can be represented by the digit key mapping.
    They require |size keys textonyms| digit combinations to represent them.
    |tcount| digit combinations represent Textonyms.

    7325 -> |textonyms\["7325"]|
}

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

7325 -> [peak peal peck real reck seal]

AWK

Works with: gawk version 5.1.0

#!/usr/bin/env -S gawk -E

BEGIN { # user's configuration area

  KEYMAP="2 abc 3 def 4 ghi 5 jkl 6 mno 7 pqrs 8 tuv 9 wxyz"
  FNAME="/usr/share/dict/american-english"     # 0.5 MB; 102775 words;

  #KEYMAP="2 αβγά 3 δεζέ 4 ηθιήίϊΐ 5 κλμ 6 νξοό 7 πρσς 8 τυφύϋΰ 9 χψωώ"
  #FNAME="/usr/share/dict/greek"               # 19.5MB; 828808 words;

              #   where generated data will be written,
              # or comment out a line if you don’t need it.
  EXPORT_TXN="/tmp/textonyms"
  EXPORT_ALL="/tmp/phonewords"
  EXPORT_BAD="/tmp/invalidwords"   #also the line ‘BUFF_ERRW = BUFF_...’
}
BEGIN { # main
  delete ARGV; ARGC=1   # do not accept command line arguments
  delete XEK            # reserve id for use only as a hash table
  delete TXN            # reserve id ...
  AZ=""                 # generated Alphabet
  EE=0                  # invalid word Counter
  KK=0                  # valid word Counter
  TT=0                  # textonym groups in the table TXN
  BUFF_ERRW=""          # invalid word buffer
  TOTAL=1               # enum
  COUNT=2               # enum

  STDERR="/dev/stderr"
  OLD_RS=RS
  OLD_FS=FS
  processFile()
  generateReport()
  userQuery()
}
function processFile(    ii,jj,nn,errW,ss,aKey,aGroup,qqq){
  $0=KEYMAP
  AZ=" "
  for (ii=1; ii<=NF; ii=ii+2) {
    aKey=$ii; aGroup=$(ii+1)
    nn=split(aGroup, qqq, //)
    for (jj=1; jj<=nn; jj++) {ss=qqq[jj]; XEK[ss]=aKey; AZ = AZ ss " " }
  }
  AZ = AZ " "
  ######################
       RS="^$"         #
       FS="[\n\t ]+"   #
  ######################      
  if ((getline <FNAME) <= 0) {
    printf "unexpected EOF or error: ‘%s’ %s\n",FNAME,ERRNO   >STDERR
    exit 1
  } else printf "total words in the file ‘%s’: %s\n", FNAME,NF
  
  for (ii=1; ii<=NF; ii++) {
    errW=0
    ss=tolower($ii)
    nn=split(ss, qqq, //)
    nmb=""
    for (jj=1; jj<=nn; jj++) {
      lchr=qqq[jj]
      if (index(AZ," "lchr" ")>0) { nmb = nmb XEK[lchr] }
      else {
        EE++
        errW=1
        BUFF_ERRW = BUFF_ERRW $ii "\n"
        break
      }
    }
    if (errW) { continue }
    T9=TXN[nmb][TOTAL]
    if (index(T9" "," "ss" ")==0) {
      TXN[nmb][TOTAL] = T9 " " ss
      TXN[nmb][COUNT]++
    }
    KK++
  }
}
function generateReport(        elm){
  for (elm in TXN) { if (TXN[elm][COUNT]>1) { TT++ } }
  printf "valid words:                   %9s\n", KK
  printf "invalid words:                 %9s\n", EE
  printf "table indices for valid words: %9s\n", length(TXN)
  printf "textonym groups in the table:  %9s\n", TT
  exportData()
  close(EXPORT_BAD); close(EXPORT_TXN); close(EXPORT_ALL)
}
function exportData(        elm){
  if (EXPORT_BAD != "") print BUFF_ERRW  >EXPORT_BAD

  if (EXPORT_TXN != "" && EXPORT_ALL != "") {
    printf "%s\n",
       "number-of-textonyms\tword's-length\tkeys\tlist-of-textonyms" >EXPORT_ALL
    printf "%s\n",
       "number-of-textonyms\tword's-length\tkeys\tlist-of-textonyms" >EXPORT_TXN
    for (elm in TXN) {
      printf "%s\t%s\t%s\t%s\n",
                 TXN[elm][COUNT], length(elm), elm, TXN[elm][TOTAL]  >EXPORT_ALL
      if (TXN[elm][COUNT]>1) {
        printf "%s\t%s\t%s\t%s\n",
                 TXN[elm][COUNT], length(elm), elm, TXN[elm][TOTAL]  >EXPORT_TXN
      }
    }
    return ## return ## return ## return ##
  } else if (EXPORT_ALL != "") {
      printf "%s\n",
       "number-of-textonyms\tword's-length\tkeys\tlist-of-textonyms" >EXPORT_ALL
      for (elm in TXN) {
        printf "%s\t%s\t%s\t%s\n",
               TXN[elm][COUNT], length(elm), elm, TXN[elm][TOTAL]    >EXPORT_ALL
      }
  }
  else if (EXPORT_TXN != "") {
    printf "%s\n",
       "number-of-textonyms\tword's-length\tkeys\tlist-of-textonyms" >EXPORT_TXN
    for (elm in TXN) {
      if (TXN[elm][COUNT]>1) {
        printf "%s\t%s\t%s\t%s\n",
                 TXN[elm][COUNT], length(elm), elm, TXN[elm][TOTAL]  >EXPORT_TXN
      }
    }
  }
}
function userQuery(        userasks,ss,ss1,nn,key,words){
  printf "txn>> "
  RS=OLD_RS
  FS=OLD_FS
  while ((getline ) > 0) {
    userasks=$1
    if (NF==0){  printf "txn>> ", "";  continue }
    else if (userasks ~ /^-e|--ex|--exit$/) { exit }
    else if (userasks ~ /^[0-9]+$/) {
      nn=TXN[userasks][COUNT]+0
      words=TXN[userasks][TOTAL]
      if (nn == 0) { printf "%s -> %s\n", userasks,"no matching words" }
      else {         printf "%s -> (%s) %s\n", userasks,nn,words }
    }
    else {
      ss=tolower(userasks)
      if ((key=keySeq_orElse_zero(ss))>0) {
         ss1=(index((TXN[key][TOTAL]" ") , " "ss" ")>0) ? 
            ", and the word is in" : ", but the word is not in"
         printf "%s -> %s; the key is%s in the table%s\n", ss,key,
               ((key in TXN) ?"":" not"),ss1
      }
      else {
        printf "%s -> not a valid word for the alphabet:\n%s\n", userasks,AZ
      }
    }
    printf "txn>> "
  }
  printf "\n"
}
function keySeq_orElse_zero(aWord,        qqq,lchr,nn,jj,buf){
  nn=split(aWord, qqq, //)
  for (jj=1; jj<=nn; jj++) {
    lchr=qqq[jj]
    if (index(AZ," "lchr" ")>0) { buf = buf XEK[lchr] } else { return 0 }
  }
  return buf
}

Output:

# Run, assuming the code is in the txn.awk
$ LANG=en_US.UTF-8  ./txn.awk
total words in the file ‘/usr/share/dict/american-english’: 102775
valid words:                       73318
invalid words:                     29457
table indices for valid words:     65817
textonym groups in the table:       4670
txn>> cafe
cafe -> 2233; the key is in the table, but the word is not in
txn>> 2233
2233 -> (3)  abed aced bade
txn>> café
café -> not a valid word for the alphabet:
 a b c d e f g h i j k l m n o p q r s t u v w x y z  
txn>> --exit
$ 
$ 
$ egrep 'café' "/tmp/invalidwords"
café
café's
cafés
$ 
$ sort -n -b -k 1 "/tmp/textonyms" | tail -n 7
8	6	782537	 quaker pucker quakes rubles stakes staler stales sucker
9	3	269	 amy bmw cox coy any bow box boy cow
9	4	2273	 case acre bard bare barf base cape card care
9	4	7277	 parr sars paps pars pass raps rasp saps sass
9	4	7867	 pump puns rump rums runs stop sump sums suns
9	5	46637	 homer goner goods goofs homes hones hoods hoofs inner
12	5	22737	 acres bards barer bares barfs baser bases caper capes cards cares cases
$ 
$ 
$ sort -n -b -k 2 "/tmp/phonewords" | tail -n 5
1	20	86242722837478422559	 uncharacteristically
1	21	353287636237425647267	 electroencephalograms
1	21	353287636237425647274	 electroencephalograph
1	22	2686837738658846627437	 counterrevolutionaries
1	22	3532876362374256472747	 electroencephalographs
$

C

Library: GLib

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <glib.h>

char text_char(char c) {
    switch (c) {
    case 'a': case 'b': case 'c':
        return '2';
    case 'd': case 'e': case 'f':
        return '3';
    case 'g': case 'h': case 'i':
        return '4';
    case 'j': case 'k': case 'l':
        return '5';
    case 'm': case 'n': case 'o':
        return '6';
    case 'p': case 'q': case 'r': case 's':
        return '7';
    case 't': case 'u': case 'v':
        return '8';
    case 'w': case 'x': case 'y': case 'z':
        return '9';
    default:
        return 0;
    }
}

bool text_string(const GString* word, GString* text) {
    g_string_set_size(text, word->len);
    for (size_t i = 0; i < word->len; ++i) {
        char c = text_char(g_ascii_tolower(word->str[i]));
        if (c == 0)
            return false;
        text->str[i] = c;
    }
    return true;
}

typedef struct textonym_tag {
    const char* text;
    size_t length;
    GPtrArray* words;
} textonym_t;

int compare_by_text_length(const void* p1, const void* p2) {
    const textonym_t* t1 = p1;
    const textonym_t* t2 = p2;
    if (t1->length > t2->length)
        return -1;
    if (t1->length < t2->length)
        return 1;
    return strcmp(t1->text, t2->text);
}

int compare_by_word_count(const void* p1, const void* p2) {
    const textonym_t* t1 = p1;
    const textonym_t* t2 = p2;
    if (t1->words->len > t2->words->len)
        return -1;
    if (t1->words->len < t2->words->len)
        return 1;
    return strcmp(t1->text, t2->text);
}

void print_words(GPtrArray* words) {
    for (guint i = 0, n = words->len; i < n; ++i) {
        if (i > 0)
            printf(", ");
        printf("%s", g_ptr_array_index(words, i));
    }
    printf("\n");
}

void print_top_words(GArray* textonyms, guint top) {
    for (guint i = 0; i < top; ++i) {
        const textonym_t* t = &g_array_index(textonyms, textonym_t, i);
        printf("%s = ", t->text);
        print_words(t->words);
    }
}

void free_strings(gpointer ptr) {
    g_ptr_array_free(ptr, TRUE);
}

bool find_textonyms(const char* filename, GError** error_ptr) {
    GError* error = NULL;
    GIOChannel* channel = g_io_channel_new_file(filename, "r", &error);
    if (channel == NULL) {
        g_propagate_error(error_ptr, error);
        return false;
    }
    GHashTable* ht = g_hash_table_new_full(g_str_hash, g_str_equal,
                                           g_free, free_strings);
    GString* word = g_string_sized_new(64);
    GString* text = g_string_sized_new(64);
    guint count = 0;
    gsize term_pos;
    while (g_io_channel_read_line_string(channel, word, &term_pos,
                                         &error) == G_IO_STATUS_NORMAL) {
        g_string_truncate(word, term_pos);
        if (!text_string(word, text))
            continue;
        GPtrArray* words = g_hash_table_lookup(ht, text->str);
        if (words == NULL) {
            words = g_ptr_array_new_full(1, g_free);
            g_hash_table_insert(ht, g_strdup(text->str), words);
        }
        g_ptr_array_add(words, g_strdup(word->str));
        ++count;
    }
    g_io_channel_unref(channel);
    g_string_free(word, TRUE);
    g_string_free(text, TRUE);
    if (error != NULL) {
        g_propagate_error(error_ptr, error);
        g_hash_table_destroy(ht);
        return false;
    }

    GArray* words = g_array_new(FALSE, FALSE, sizeof(textonym_t));
    GHashTableIter iter;
    gpointer key, value;
    g_hash_table_iter_init(&iter, ht);
    while (g_hash_table_iter_next(&iter, &key, &value)) {
        GPtrArray* v = value;
        if (v->len > 1) {
            textonym_t textonym;
            textonym.text = key;
            textonym.length = strlen(key);
            textonym.words = v;
            g_array_append_val(words, textonym);
        }
    }

    printf("There are %u words in '%s' which can be represented by the digit key mapping.\n",
           count, filename);
    guint size = g_hash_table_size(ht);
    printf("They require %u digit combinations to represent them.\n", size);
    guint textonyms = words->len;
    printf("%u digit combinations represent Textonyms.\n", textonyms);

    guint top = 5;
    if (textonyms < top)
        top = textonyms;

    printf("\nTop %u by number of words:\n", top);
    g_array_sort(words, compare_by_word_count);
    print_top_words(words, top);
    
    printf("\nTop %u by length:\n", top);
    g_array_sort(words, compare_by_text_length);
    print_top_words(words, top);

    g_array_free(words, TRUE);
    g_hash_table_destroy(ht);
    return true;
}

int main(int argc, char** argv) {
    if (argc != 2) {
        fprintf(stderr, "usage: %s word-list\n", argv[0]);
        return EXIT_FAILURE;
    }
    GError* error = NULL;
    if (!find_textonyms(argv[1], &error)) {
        if (error != NULL) {
            fprintf(stderr, "%s: %s\n", argv[1], error->message);
            g_error_free(error);
        }
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

Output:

There are 24978 words in 'unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 by number of words:
269 = amy, any, bmw, bow, box, boy, cow, cox, coy
729 = paw, pax, pay, paz, raw, ray, saw, sax, say
2273 = acre, bard, bare, base, cape, card, care, case
726 = pam, pan, ram, ran, sam, san, sao, scm
426 = gam, gao, ham, han, ian, ibm, ibn

Top 5 by length:
25287876746242 = claustrophobia, claustrophobic
7244967473642 = schizophrenia, schizophrenic
666628676342 = onomatopoeia, onomatopoeic
49376746242 = hydrophobia, hydrophobic
2668368466 = contention, convention

C++

#include <fstream>
#include <iostream>
#include <unordered_map>
#include <vector>

struct Textonym_Checker {
private:
    int total;
    int elements;
    int textonyms;
    int max_found;
    std::vector<std::string> max_strings;
    std::unordered_map<std::string, std::vector<std::string>> values;

    int get_mapping(std::string &result, const std::string &input)
    {
        static std::unordered_map<char, char> mapping = {
            {'A', '2'}, {'B', '2'}, {'C', '2'},
            {'D', '3'}, {'E', '3'}, {'F', '3'},
            {'G', '4'}, {'H', '4'}, {'I', '4'},
            {'J', '5'}, {'K', '5'}, {'L', '5'},
            {'M', '6'}, {'N', '6'}, {'O', '6'},
            {'P', '7'}, {'Q', '7'}, {'R', '7'}, {'S', '7'},
            {'T', '8'}, {'U', '8'}, {'V', '8'},
            {'W', '9'}, {'X', '9'}, {'Y', '9'}, {'Z', '9'}
        };

        result = input;
        for (char &c : result) {
            if (!isalnum(c)) return 0;
            if (isalpha(c)) c = mapping[toupper(c)];
        }

        return 1;
    }

public:
    Textonym_Checker() : total(0), elements(0), textonyms(0), max_found(0) { }

    ~Textonym_Checker() { }

    void add(const std::string &str) {
        std::string mapping;
        total++;

        if (!get_mapping(mapping, str)) return;

        const int num_strings = values[mapping].size();

        if (num_strings == 1) textonyms++;
        elements++;

        if (num_strings > max_found) {
            max_strings.clear();
            max_strings.push_back(mapping);
            max_found = num_strings;
        }
        else if (num_strings == max_found)
            max_strings.push_back(mapping);

        values[mapping].push_back(str);
    }

    void results(const std::string &filename) {
        std::cout << "Read " << total << " words from " << filename << "\n\n";

        std::cout << "There are " << elements << " words in " << filename;
        std::cout << " which can be represented by the digit key mapping.\n";
        std::cout << "They require " << values.size() <<
                     " digit combinations to represent them.\n";
        std::cout << textonyms << " digit combinations represent Textonyms.\n\n";
        std::cout << "The numbers mapping to the most words map to ";
        std::cout << max_found + 1 << " words each:\n";

        for (auto it1 : max_strings) {
            std::cout << '\t' << it1 << " maps to: ";
            for (auto it2 : values[it1])
                std::cout << it2 << " ";
            std::cout << '\n';
        }
        std::cout << '\n';
    }

    void match(const std::string &str) {
        auto match = values.find(str);

        if (match == values.end()) {
            std::cout << "Key '" << str << "' not found\n";
        }
        else {
            std::cout << "Key '" << str << "' matches: ";
            for (auto it : values[str])
                std::cout << it << " ";
            std::cout << '\n';
        }
    }
};

int main()
{
    auto filename = "unixdict.txt";
    std::ifstream input(filename);
    Textonym_Checker tc;

    if (input.is_open()) {
        std::string line;
        while (getline(input, line))
            tc.add(line);
    }

    input.close();

    tc.results(filename);
    tc.match("001");
    tc.match("228");
    tc.match("27484247");
    tc.match("7244967473642");
}

Output:

Read 25104 words from unixdict.txt

There are 24988 words in unixdict.txt which can be represented by the digit key mapping.
They require 22905 digit combinations to represent them.
1477 digit combinations represent Textonyms.

The numbers mapping to the most words map to 9 words each:
	269 maps to: amy any bmw bow box boy cow cox coy 
	729 maps to: paw pax pay paz raw ray saw sax say 

Key '001' not found
Key '228' matches: aau act bat cat 
Key '27484247' not found
Key '7244967473642' matches: schizophrenia schizophrenic

Clojure

The Tcl example counts all the words which share a digit sequence with another word. Like the other examples, this considers a textonym to be a digit sequence which maps to more than one word.

(def table
  {\a 2 \b 2 \c 2       \A 2 \B 2 \C 2
   \d 3 \e 3 \f 3       \D 3 \E 3 \F 3
   \g 4 \h 4 \i 4       \G 4 \H 4 \I 4
   \j 5 \k 5 \l 5       \J 5 \K 5 \L 5
   \m 6 \n 6 \o 6       \M 6 \N 6 \O 6
   \p 7 \q 7 \r 7 \s 7  \P 7 \Q 7 \R 7 \S 7
   \t 8 \u 8 \v 8       \T 8 \U 8 \V 8
   \w 9 \x 9 \y 9 \z 9  \W 9 \X 9 \Y 9 \Z 9})

(def words-url "http://www.puzzlers.org/pub/wordlists/unixdict.txt")

(def words (-> words-url slurp clojure.string/split-lines))

(def digits (partial map table))

(let [textable  (filter #(every? table %) words) ;; words with letters only
      mapping   (group-by digits textable)       ;; map of digits to words
      textonyms (filter #(< 1 (count (val %))) mapping)] ;; textonyms only
  (print 
   (str "There are " (count textable) " words in " \' words-url \'
        " which can be represented by the digit key mapping. They require "
        (count mapping) " digit combinations to represent them. "
        (count textonyms) " digit combinations represent Textonyms.")))

Output:

There are 24978 words in 'http://www.puzzlers.org/pub/wordlists/unixdict.txt' which can be represented by the digit key mapping. They require 22903 digit combinations to represent them. 1473 digit combinations represent Textonyms.

Crystal

filename = "unixdict.txt"
from = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
to   = "2223334445556667777888999922233344455566677778889999"

mapping = File.read(filename).each_line.reject(/[^A-Za-z]/).group_by {|w| w.tr(from, to) }
textonyms = mapping.select { |k, v| v.size > 1 }

nwords = mapping.values.map(&.size).sum

puts "There are #{nwords} words in #{filename} which can be represented by the digit key mapping."
puts "They require #{mapping.size} digit combinations to represent them."
puts "#{textonyms.size} digit combinations represent Textonyms."

# let's find something original

repeated = mapping.keys.select(/^(.)\1\1+$/).sort_by(&.size).reverse
puts
puts "Least-effort words"
repeated.each do |w|
  puts "  #{w}\t #{mapping[w].join(", ")}"
end

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Least-effort words
  22222  ababa
  8888   tutu
  6666   moon, noon
  4444   high
  3333   deed, feed
  666    moo, non
  444    gig, iii
  333    dee, fed, fee
  222    aaa, aba, abc, cab

D

Translation of: Raku

void main() {
    import std.stdio, std.string, std.range, std.algorithm, std.ascii;

    immutable src = "unixdict.txt";
    const words = src.File.byLineCopy.map!strip.filter!(w => w.all!isAlpha).array;

    immutable table = makeTrans("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
                                "2223334445556667777888999922233344455566677778889999");

    string[][string] dials;
    foreach (const word; words)
        dials[word.translate(table)] ~= word;

    auto textonyms = dials.byPair.filter!(p => p[1].length > 1).array;

    writefln("There are %d words in %s which can be represented by the digit key mapping.", words.length, src);
    writefln("They require %d digit combinations to represent them.", dials.length);
    writefln("%d digit combinations represent Textonyms.", textonyms.length);

    "\nTop 5 in ambiguity:".writeln;
    foreach (p; textonyms.schwartzSort!(p => -p[1].length).take(5))
        writefln("    %s => %-(%s %)", p[]);

    "\nTop 5 in length:".writeln;
    foreach (p; textonyms.schwartzSort!(p => -p[0].length).take(5))
        writefln("    %s => %-(%s %)", p[]);
}

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 in ambiguity:
    729 => paw pax pay paz raw ray saw sax say
    269 => amy any bmw bow box boy cow cox coy
    2273 => acre bard bare base cape card care case
    726 => pam pan ram ran sam san sao scm
    426 => gam gao ham han ian ibm ibn

Top 5 in length:
    25287876746242 => claustrophobia claustrophobic
    7244967473642 => schizophrenia schizophrenic
    666628676342 => onomatopoeia onomatopoeic
    49376746242 => hydrophobia hydrophobic
    6388537663 => mettlesome nettlesome

Delphi

Library: System.SysUtils

Library: System.Classes

Library: System.Generics.Collections

Library: System.Character

Translation of: C++

program Textonyms;

{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  System.Classes,
  System.Generics.Collections,
  System.Character;

const
  TEXTONYM_MAP = '22233344455566677778889999';

type
  TextonymsChecker = class
  private
    Total, Elements, Textonyms, MaxFound: Integer;
    MaxStrings: TList<string>;
    Values: TDictionary<string, TList<string>>;
    FFileName: TFileName;
    function Map(c: Char): Char;
    function GetMapping(var return: string; const Input: string): Boolean;
  public
    constructor Create(FileName: TFileName);
    destructor Destroy; override;
    procedure Add(const Str: string);
    procedure Load(FileName: TFileName);
    procedure Test;
    function Match(const str: string): Boolean;
    property FileName: TFileName read FFileName;
  end;

{ TextonymsChecker }

procedure TextonymsChecker.Add(const Str: string);
var
  mapping: string;
  num_strings: Integer;

  procedure AddValues(mapping: string; NewItem: string);
  begin
    if not Values.ContainsKey(mapping) then
      Values.Add(mapping, TList<string>.Create);

    Values[mapping].Add(NewItem);
  end;

begin
  inc(total);

  if not GetMapping(mapping, Str) then
    Exit;

  if Values.ContainsKey(mapping) then
    num_strings := Values[mapping].Count
  else
    num_strings := 0;

  inc(Textonyms, ord(num_strings = 1));
  inc(Elements);

  if (num_strings > maxfound) then
  begin
    MaxStrings.Clear;
    MaxStrings.Add(mapping);
    MaxFound := num_strings;
  end
  else if num_strings = MaxFound then
  begin
    MaxStrings.Add(mapping);
  end;

  AddValues(mapping, Str);
end;

constructor TextonymsChecker.Create(FileName: TFileName);
begin
  MaxStrings := TList<string>.Create;
  Values := TDictionary<string, TList<string>>.Create;
  Total := 0;
  Textonyms := 0;
  MaxFound := 0;
  Elements := 0;
  Load(FileName);
end;

destructor TextonymsChecker.Destroy;
var
  key: string;
begin
  for key in Values.Keys do
    Values[key].Free;

  Values.Free;
  MaxStrings.Free;
  inherited;
end;

function TextonymsChecker.GetMapping(var return: string; const Input: string): Boolean;
var
  i: Integer;
begin
  return := Input;
  for i := 1 to return.Length do
  begin
    if not return[i].IsLetterOrDigit then
      exit(False);

    if return[i].IsLetter then
      return[i] := Map(return[i]);
  end;
  Result := True;
end;

procedure TextonymsChecker.Load(FileName: TFileName);
var
  i: Integer;
begin
  if not FileExists(FileName) then
  begin
    writeln('File "', FileName, '" not found');
    exit;
  end;

  with TStringList.Create do
  begin
    LoadFromFile(FileName);
    for i := 0 to count - 1 do
    begin
      self.Add(Strings[i]);
    end;
    Free;
  end;
end;

function TextonymsChecker.Map(c: Char): Char;
begin
  Result := TEXTONYM_MAP.Chars[Ord(UpCase(c)) - Ord('A')];
end;

function TextonymsChecker.Match(const str: string): Boolean;
var
  w: string;
begin
  Result := Values.ContainsKey(str);

  if not Result then
  begin
    writeln('Key "', str, '" not found');
  end
  else
  begin
    write('Key "', str, '" matches: ');
    for w in Values[str] do
    begin
      write(w, ' ');
    end;
    writeln;
  end;
end;

procedure TextonymsChecker.Test;
var
  i, j: Integer;
begin
  writeln('Read ', Total, ' words from ', FileName, #10);
  writeln(' which can be represented by the digit key mapping.');
  writeln('They require ', Values.Count, ' digit combinations to represent them.');
  writeln(textonyms, ' digit combinations represent Textonyms.', #10);
  write('The numbers mapping to the most words map to');
  writeln(MaxFound + 1, ' words each:');

  for i := 0 to MaxStrings.Count - 1 do
  begin
    write(^I, MaxStrings[i], ' maps to: ');
    for j := 0 to Values[MaxStrings[i]].Count - 1 do
    begin
      write(Values[MaxStrings[i]][j], ' ');
    end;
    Writeln;
  end;

end;

var
  Tc: TextonymsChecker;

begin
  Tc := TextonymsChecker.Create('unixdict.txt');
  Tc.Test;

  tc.match('001');
  tc.match('228');
  tc.match('27484247');
  tc.match('7244967473642');

  Tc.Free;
  readln;
end.

Output:

Read 25104 words from

 which can be represented by the digit key mapping.
They require 22905 digit combinations to represent them.
1477 digit combinations represent Textonyms.

The numbers mapping to the most words map to9 words each:
        269 maps to: amy any bmw bow box boy cow cox coy
        729 maps to: paw pax pay paz raw ray saw sax say
Key "001" not found
Key "228" matches: aau act bat cat
Key "27484247" not found
Key "7244967473642" matches: schizophrenia schizophrenic

Factor

Works with: Factor version 0.99 2020-07-03

USING: assocs assocs.extras interpolate io io.encodings.utf8
io.files kernel literals math math.parser prettyprint sequences
unicode ;

<< CONSTANT: src "unixdict.txt" >>

CONSTANT: words
    $[ src utf8 file-lines [ [ letter? ] all? ] filter ]

CONSTANT: digits "22233344455566677778889999"

: >phone ( str -- n )
    [ CHAR: a - digits nth ] map string>number ;

: textonyms ( seq -- assoc )
    [ [ >phone ] keep ] map>alist expand-keys-push-at ;

: #textonyms ( assoc -- n )
    [ nip length 1 > ] assoc-filter assoc-size ;

words length src words textonyms [ assoc-size ] keep #textonyms

[I There are ${} words in ${} which can be represented by the digit key mapping.
They require ${} digit combinations to represent them.
${} digit combinations represent Textonyms.I] nl nl

"7325 -> " write words textonyms 7325 of .

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

7325 -> V{ "peak" "peal" "peck" "real" "reck" "seal" }

FreeBASIC

Type KeyValuePair
    As String key
    As String value
End Type

' Simulate a dictionary with an array
Dim Shared keyMap(0 To 7) As KeyValuePair
keyMap(0).key = "ABC" : keyMap(0).value = "2"
keyMap(1).key = "DEF" : keyMap(1).value = "3"
keyMap(2).key = "GHI" : keyMap(2).value = "4"
keyMap(3).key = "JKL" : keyMap(3).value = "5"
keyMap(4).key = "MNO" : keyMap(4).value = "6"
keyMap(5).key = "PQRS" : keyMap(5).value = "7"
keyMap(6).key = "TUV" : keyMap(6).value = "8"
keyMap(7).key = "WXYZ" : keyMap(7).value = "9"

Function GetKeyMapValue(char As String) As String
    For i As Integer = Lbound(keyMap) To Ubound(keyMap)
        If Instr(keyMap(i).key, Ucase(char)) > 0 Then Return keyMap(i).value
    Next
    Return ""
End Function

Function ArrayExists(arr() As String, value As String) As Boolean
    For i As Integer = Lbound(arr) To Ubound(arr)
        If arr(i) = value Then Return True
    Next
    Return False
End Function

Dim As Integer TotalWords = 0
Dim As Integer UniqueCombinations = 0
Dim As String uniqueWords(), moreThanOneWord()

Dim As String inputFile = "unixdict.txt"
Dim As Integer ff = Freefile()
Open inputFile For Input As #ff
If Err <> 0 Then Print "Error: Unable to open file '" & inputFile & "'": End 1

Dim As String linea, num, char, digit
Dim As Integer c, i
Do Until Eof(ff)
    Line Input #ff, linea
    If Len(linea) > 0 Then
        num = ""
        c = 0
        For i = 1 To Len(linea)
            char = Mid(linea, i, 1)
            digit = GetKeyMapValue(char)
            If digit <> "" Then
                num &= digit
                c += 1
            End If
        Next i
        
        If c = Len(linea) Then
            TotalWords += 1
            If Ubound(uniqueWords) = -1 Orelse Not ArrayExists(uniqueWords(), num) Then
                Redim Preserve uniqueWords(0 To Ubound(uniqueWords) + 1)
                uniqueWords(Ubound(uniqueWords)) = num
                UniqueCombinations += 1
            Else
                If Ubound(moreThanOneWord) = -1 Orelse Not ArrayExists(moreThanOneWord(), num) Then
                    Redim Preserve moreThanOneWord(0 To Ubound(moreThanOneWord) + 1)
                    moreThanOneWord(Ubound(moreThanOneWord)) = num
                End If
            End If
        End If
    End If
Loop

Close #ff

Print "There are " & TotalWords & " words in ""unixdict.txt"" which can be represented by the digit key mapping."
Print "They require " & UniqueCombinations & " digit combinations to represent them."
Print Ubound(moreThanOneWord) + 1 & " digit combinations represent Textonyms."

Sleep

Output:

Same as VBScript entry.

Go

Uses a local file and shows its name rather than re-fetching a URL each run and printing that URL.

Like the Phython example, the examples shown are the numbers that map to the most words.

package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"strings"
	"unicode"
)

func main() {
	log.SetFlags(0)
	log.SetPrefix("textonyms: ")

	wordlist := flag.String("wordlist", "wordlist", "file containing the list of words to check")
	flag.Parse()
	if flag.NArg() != 0 {
		flag.Usage()
		os.Exit(2)
	}

	t := NewTextonym(phoneMap)
	_, err := ReadFromFile(t, *wordlist)
	if err != nil {
		log.Fatal(err)
	}
	t.Report(os.Stdout, *wordlist)
}

// phoneMap is the digit to letter mapping of a typical phone.
var phoneMap = map[byte][]rune{
	'2': []rune("ABC"),
	'3': []rune("DEF"),
	'4': []rune("GHI"),
	'5': []rune("JKL"),
	'6': []rune("MNO"),
	'7': []rune("PQRS"),
	'8': []rune("TUV"),
	'9': []rune("WXYZ"),
}

// ReadFromFile is a generic convience function that allows the use of a
// filename with an io.ReaderFrom and handles errors related to open and
// closing the file.
func ReadFromFile(r io.ReaderFrom, filename string) (int64, error) {
	f, err := os.Open(filename)
	if err != nil {
		return 0, err
	}
	n, err := r.ReadFrom(f)
	if cerr := f.Close(); err == nil && cerr != nil {
		err = cerr
	}
	return n, err
}

type Textonym struct {
	numberMap map[string][]string // map numeric string into words
	letterMap map[rune]byte       // map letter to digit
	count     int                 // total number of words in numberMap
	textonyms int                 // number of numeric strings with >1 words
}

func NewTextonym(dm map[byte][]rune) *Textonym {
	lm := make(map[rune]byte, 26)
	for d, ll := range dm {
		for _, l := range ll {
			lm[l] = d
		}
	}
	return &Textonym{letterMap: lm}
}

func (t *Textonym) ReadFrom(r io.Reader) (n int64, err error) {
	t.numberMap = make(map[string][]string)
	buf := make([]byte, 0, 32)
	sc := bufio.NewScanner(r)
	sc.Split(bufio.ScanWords)
scan:
	for sc.Scan() {
		buf = buf[:0]
		word := sc.Text()

		// XXX we only bother approximating the number of bytes
		// consumed. This isn't used in the calling code and was
		// only included to match the io.ReaderFrom interface.
		n += int64(len(word)) + 1

		for _, r := range word {
			d, ok := t.letterMap[unicode.ToUpper(r)]
			if !ok {
				//log.Printf("ignoring %q\n", word)
				continue scan
			}
			buf = append(buf, d)
		}
		//log.Printf("scanned %q\n", word)
		num := string(buf)
		t.numberMap[num] = append(t.numberMap[num], word)
		t.count++
		if len(t.numberMap[num]) == 2 {
			t.textonyms++
		}
		//log.Printf("%q → %v\t→ %v\n", word, num, t.numberMap[num])
	}
	return n, sc.Err()
}

func (t *Textonym) Most() (most int, subset map[string][]string) {
	for k, v := range t.numberMap {
		switch {
		case len(v) > most:
			subset = make(map[string][]string)
			most = len(v)
			fallthrough
		case len(v) == most:
			subset[k] = v
		}
	}
	return most, subset
}

func (t *Textonym) Report(w io.Writer, name string) {
	// Could be fancy and use text/template package but fmt is sufficient
	fmt.Fprintf(w, `
There are %v words in %q which can be represented by the digit key mapping.
They require %v digit combinations to represent them.
%v digit combinations represent Textonyms.
`,
		t.count, name, len(t.numberMap), t.textonyms)

	n, sub := t.Most()
	fmt.Fprintln(w, "\nThe numbers mapping to the most words map to",
		n, "words each:")
	for k, v := range sub {
		fmt.Fprintln(w, "\t", k, "maps to:", strings.Join(v, ", "))
	}
}

Output:

There are 13085 words in "wordlist" which can be represented by the digit key mapping.
They require 11932 digit combinations to represent them.
661 digit combinations represent Textonyms.

The numbers mapping to the most words map to 15 words each:
	 27 maps to: AP, AQ, AR, AS, Ar, As, BP, BR, BS, Br, CP, CQ, CR, Cr, Cs

Output with "-wordlist unixdict.txt":

There are 24978 words in "unixdict.txt" which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

The numbers mapping to the most words map to 9 words each:
	 269 maps to: amy, any, bmw, bow, box, boy, cow, cox, coy
	 729 maps to: paw, pax, pay, paz, raw, ray, saw, sax, say

Haskell

import Data.Char (toUpper)
import Data.Function (on)
import Data.List (groupBy, sortBy)
import Data.Maybe (fromMaybe, isJust, isNothing)

toKey :: Char -> Maybe Char
toKey ch
  | ch < 'A' = Nothing
  | ch < 'D' = Just '2'
  | ch < 'G' = Just '3'
  | ch < 'J' = Just '4'
  | ch < 'M' = Just '5'
  | ch < 'P' = Just '6'
  | ch < 'T' = Just '7'
  | ch < 'W' = Just '8'
  | ch <= 'Z' = Just '9'
  | otherwise = Nothing

toKeyString :: String -> Maybe String
toKeyString st
  | any isNothing mch = Nothing
  | otherwise = Just $ map (fromMaybe '!') mch
  where
    mch = map (toKey . toUpper) st

showTextonym :: [(String, String)] -> String
showTextonym ts =
  fst (head ts)
    ++ " => "
    ++ concat
      [ w ++ " "
        | (_, w) <- ts
      ]

main :: IO ()
main = do
  let src = "unixdict.txt"
  contents <- readFile src
  let wordList = lines contents
      keyedList =
        [ (key, word)
          | (Just key, word) <-
              filter (isJust . fst) $
                zip (map toKeyString wordList) wordList
        ]
      groupedList =
        groupBy ((==) `on` fst) $
          sortBy (compare `on` fst) keyedList
      textonymList = filter ((> 1) . length) groupedList
  mapM_ putStrLn $
    [ "There are "
        ++ show (length keyedList)
        ++ " words in "
        ++ src
        ++ " which can be represented by the digit key mapping.",
      "They require "
        ++ show (length groupedList)
        ++ " digit combinations to represent them.",
      show (length textonymList) ++ " digit combinations represent Textonyms.",
      "",
      "Top 5 in ambiguity:"
    ]
      ++ fmap
        showTextonym
        ( take 5 $
            sortBy (flip compare `on` length) textonymList
        )
      ++ ["", "Top 5 in length:"]
      ++ fmap
        showTextonym
        (take 5 $ sortBy (flip compare `on` (length . fst . head)) textonymList)

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 in ambiguity:
269 => amy any bmw bow box boy cow cox coy 
729 => paw pax pay paz raw ray saw sax say 
2273 => acre bard bare base cape card care case 
726 => pam pan ram ran sam san sao scm 
426 => gam gao ham han ian ibm ibn 

Top 5 in length:
25287876746242 => claustrophobia claustrophobic 
7244967473642 => schizophrenia schizophrenic 
666628676342 => onomatopoeia onomatopoeic 
49376746242 => hydrophobia hydrophobic 
2668368466 => contention convention

Or, in terms of Data.Map and traverse:

import Data.Function (on)
import Data.List (groupBy, maximum, sortBy, sortOn)
import qualified Data.Map as M
import Data.Maybe (mapMaybe)
import Data.Ord (comparing)

------------------------ TEXTONYMS -----------------------

digitEncoded ::
  M.Map Char Char ->
  [String] ->
  [(String, String)]
digitEncoded dict =
  mapMaybe $
    ((>>=) . traverse (`M.lookup` dict))
      <*> curry Just

charDict :: M.Map Char Char
charDict =
  M.fromList $
    concat $
      zipWith
        (fmap . flip (,))
        (head . show <$> [2 ..])
        (words "abc def ghi jkl mno pqrs tuv wxyz")

definedSamples ::
  Int ->
  [[(String, String)]] ->
  [[(String, String)] -> Int] ->
  [[[(String, String)]]]
definedSamples n xs fs =
  [take n . flip sortBy xs] <*> (flip . comparing <$> fs)

--------------------------- TEST -------------------------
main :: IO ()
main = do
  let fp = "unixdict.txt"
  s <- readFile fp
  let encodings = digitEncoded charDict $ lines s
      codeGroups =
        groupBy
          (on (==) snd)
          . sortOn snd
          $ encodings
      textonyms = filter ((1 <) . length) codeGroups
  mapM_
    putStrLn
    [ "There are "
        <> show (length encodings)
        <> " words in "
        <> fp
        <> " which can be represented\n"
        <> "by the digit key mapping.",
      "\nThey require "
        <> show (length codeGroups)
        <> " digit combinations to represent them.",
      show (length textonyms)
        <> " digit combinations represent textonyms.",
      ""
    ]
  let codeLength = length . snd . head
      [ambiguous, longer] =
        definedSamples
          5
          textonyms
          [length, codeLength]
      [wa, wl] =
        maximum . fmap codeLength
          <$> [ambiguous, longer]
  mapM_ putStrLn $
    "Five most ambiguous:" :
    fmap (showTextonym wa) ambiguous
      <> ( "" :
           "Five longest:" :
           fmap
             (showTextonym wl)
             longer
         )

------------------------- DISPLAY ------------------------
showTextonym :: Int -> [(String, String)] -> String
showTextonym w ts =
  concat
    [ rjust w ' ' (snd (head ts)),
      " -> ",
      unwords $ fmap fst ts
    ]
  where
    rjust n c = (drop . length) <*> (replicate n c <>)

Output:

There are 24978 words in unixdict.txt which can be represented
by the digit key mapping.

They require 22903 digit combinations to represent them.
1473 digit combinations represent textonyms.

Five most ambiguous:
 269 -> amy any bmw bow box boy cow cox coy
 729 -> paw pax pay paz raw ray saw sax say
2273 -> acre bard bare base cape card care case
 726 -> pam pan ram ran sam san sao scm
 426 -> gam gao ham han ian ibm ibn

Five longest:
25287876746242 -> claustrophobia claustrophobic
 7244967473642 -> schizophrenia schizophrenic
  666628676342 -> onomatopoeia onomatopoeic
   49376746242 -> hydrophobia hydrophobic
    2668368466 -> contention convention

Io

main := method(
    setupLetterToDigitMapping

    file := File clone openForReading("./unixdict.txt")
    words := file readLines
    file close

    wordCount := 0
    textonymCount := 0
    dict := Map clone
    words foreach(word,
        (key := word asPhoneDigits) ifNonNil(
            wordCount = wordCount+1
            value := dict atIfAbsentPut(key,list())
            value append(word)
            if(value size == 2,textonymCount = textonymCount+1)
        )
    )   
    write("There are ",wordCount," words in ",file name)
    writeln(" which can be represented by the digit key mapping.")
    writeln("They require ",dict size," digit combinations to represent them.")
    writeln(textonymCount," digit combinations represent Textonyms.")

    samplers := list(maxAmbiquitySampler, noMatchingCharsSampler)
    dict foreach(key,value,
        if(value size == 1, continue)
        samplers foreach(sampler,sampler examine(key,value))
    )
    samplers foreach(sampler,sampler report)
)

setupLetterToDigitMapping := method(
    fromChars := Sequence clone
    toChars := Sequence clone
    list(
        list("ABC", "2"), list("DEF", "3"), list("GHI", "4"),
        list("JKL", "5"), list("MNO", "6"), list("PQRS","7"),
        list("TUV", "8"), list("WXYZ","9")
    ) foreach( map,
        fromChars appendSeq(map at(0), map at(0) asLowercase)
        toChars alignLeftInPlace(fromChars size, map at(1))
    )

    Sequence asPhoneDigits := block(
        str := call target asMutable translate(fromChars,toChars)
        if( str contains(0), nil, str )
    ) setIsActivatable(true)
)   

maxAmbiquitySampler := Object clone do(
    max := list()
    samples := list()
    examine := method(key,textonyms,
        i := key size - 1
        if(i > max size - 1,
            max setSize(i+1)
            samples setSize(i+1)
        )
        nw := textonyms size
        nwmax := max at(i)
        if( nwmax isNil or nw > nwmax,
            max atPut(i,nw)
            samples atPut(i,list(key,textonyms))
        )
    )
    report := method(
        writeln("\nExamples of maximum ambiquity for each word length:")
        samples foreach(sample,
            sample ifNonNil(
                writeln("    ",sample at(0)," -> ",sample at(1) join(" "))
            )
        )
    )
)

noMatchingCharsSampler := Object clone do(
    samples := list()
    examine := method(key,textonyms,
        for(i,0,textonyms size - 2 ,
            for(j,i+1,textonyms size - 1,
                if( _noMatchingChars(textonyms at(i), textonyms at(j)),
                    samples append(list(textonyms at(i),textonyms at(j)))
                )
            )
        )
    )
    _noMatchingChars := method(t1,t2,
        t1 foreach(i,ich,
            if(ich == t2 at(i), return false)
        )
        true
    )       
    report := method(
        write("\nThere are ",samples size," textonym pairs which ")
        writeln("differ at each character position.")
        if(samples size > 10, writeln("The ten largest are:"))
        samples sortInPlace(at(0) size negate)
        if(samples size > 10,samples slice(0,10),samples) foreach(sample,
            writeln("    ",sample join(" ")," -> ",sample at(0) asPhoneDigits)
        )
    )
)

main

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Examples of maximum ambiquity for each word length:
    7 -> p q r s
    46 -> gm go ho in io
    269 -> amy any bmw bow box boy cow cox coy
    2273 -> acre bard bare base cape card care case
    42779 -> garry gassy happy harpy harry
    723353 -> paddle raffle saddle
    2667678 -> comport compost consort
    38465649 -> ethology etiology
    468376377 -> governess inverness
    6388537663 -> mettlesome nettlesome
    49376746242 -> hydrophobia hydrophobic
    666628676342 -> onomatopoeia onomatopoeic
    7244967473642 -> schizophrenia schizophrenic
    25287876746242 -> claustrophobia claustrophobic

There are 275 textonym pairs which differ at each character position.
The ten largest are:
    pistol shrunk -> 747865
    hotbed invade -> 468233
    aback cabal -> 22225
    about bantu -> 22688
    adams bebop -> 23267
    rival shuck -> 74825
    astor crump -> 27867
    knack local -> 56225
    rice shad -> 7423
    ammo coon -> 2666

J

require'regex strings web/gethttp'

strip=:dyad define
  (('(?s)',x);'') rxrplc y
)

fetch=:monad define
  txt=. '.*<pre>' strip '</pre>.*' strip gethttp y
  cutopen tolower txt-.' '
)

keys=:noun define
 2 abc
 3 def
 4 ghi
 5 jkl
 6 mno
 7 pqrs
 8 tuv
 9 wxyz
)

reporttext=:noun define
There are #{0} words in #{1} which can be represented by the digit key mapping.
They require #{2} digit combinations to represent them.
#{3} digit combinations represent Textonyms.
)

report=:dyad define
  x rplc (":&.>y),.~('#{',":,'}'"_)&.>i.#y
)

textonymrpt=:dyad define
  'digits letters'=. |:>;,&.>,&.>/&.>/"1 <;._1;._2 x
  valid=. (#~ */@e.&letters&>) fetch y NB. ignore illegals
  reps=. {&digits@(letters&i.)&.> valid NB. reps is digit seq
  reporttext report (#valid);y;(#~.reps);+/(1<#)/.~reps
)

Required example:

   keys textonymrpt 'http://rosettacode.org/wiki/Textonyms/wordlist'
There are 13085 words in http://rosettacode.org/wiki/Textonyms/wordlist which can be represented by the digit key mapping.
They require 11932 digit combinations to represent them.
661 digit combinations represent Textonyms.

In this example, the intermediate results in textonymrpt would look like this (just looking at the first 5 elements of the really big values:

   digits
22233344455566677778889999
   letters
abcdefghijklmnopqrstuvwxyz
   5{.valid
┌─┬──┬───┬───┬──┐
│a│aa│aaa│aam│ab│
└─┴──┴───┴───┴──┘
   5{.reps
┌─┬──┬───┬───┬──┐
│2│22│222│226│22│
└─┴──┴───┴───┴──┘

Here's another example:

   keys textonymrpt 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'
There are 24978 words in http://www.puzzlers.org/pub/wordlists/unixdict.txt which can be represnted by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Java

Translation of: c++

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Vector;

public class RTextonyms {

  private static final Map<Character, Character> mapping;
  private int total, elements, textonyms, max_found;
  private String filename, mappingResult;
  private Vector<String> max_strings;
  private Map<String, Vector<String>> values;

  static {
    mapping = new HashMap<Character, Character>();
    mapping.put('A', '2'); mapping.put('B', '2'); mapping.put('C', '2');
    mapping.put('D', '3'); mapping.put('E', '3'); mapping.put('F', '3');
    mapping.put('G', '4'); mapping.put('H', '4'); mapping.put('I', '4');
    mapping.put('J', '5'); mapping.put('K', '5'); mapping.put('L', '5');
    mapping.put('M', '6'); mapping.put('N', '6'); mapping.put('O', '6');
    mapping.put('P', '7'); mapping.put('Q', '7'); mapping.put('R', '7'); mapping.put('S', '7');
    mapping.put('T', '8'); mapping.put('U', '8'); mapping.put('V', '8');
    mapping.put('W', '9'); mapping.put('X', '9'); mapping.put('Y', '9'); mapping.put('Z', '9');
  }

  public RTextonyms(String filename) {

    this.filename = filename;
    this.total = this.elements = this.textonyms = this.max_found = 0;
    this.values = new HashMap<String, Vector<String>>();
    this.max_strings = new Vector<String>();

    return;
  }

  public void add(String line) {

    String mapping = "";
    total++;
    if (!get_mapping(line)) {
      return;
    }
    mapping = mappingResult;

    if (values.get(mapping) == null) {
      values.put(mapping, new Vector<String>());
    }

    int num_strings;
    num_strings = values.get(mapping).size();
    textonyms += num_strings == 1 ? 1 : 0;
    elements++;

    if (num_strings > max_found) {
      max_strings.clear();
      max_strings.add(mapping);
      max_found = num_strings;
    }
    else if (num_strings == max_found) {
      max_strings.add(mapping);
    }

    values.get(mapping).add(line);

    return;
  }

  public void results() {

    System.out.printf("Read %,d words from %s%n%n", total, filename);
    System.out.printf("There are %,d words in %s which can be represented by the digit key mapping.%n", elements,
        filename);
    System.out.printf("They require %,d digit combinations to represent them.%n", values.size());
    System.out.printf("%,d digit combinations represent Textonyms.%n", textonyms);
    System.out.printf("The numbers mapping to the most words map to %,d words each:%n", max_found + 1);
    for (String key : max_strings) {
      System.out.printf("%16s maps to: %s%n", key, values.get(key).toString());
    }
    System.out.println();

    return;
  }

  public void match(String key) {

    Vector<String> match;
    match = values.get(key);
    if (match == null) {
      System.out.printf("Key %s not found%n", key);
    }
    else {
      System.out.printf("Key %s matches: %s%n", key, match.toString());
    }

    return;
  }

  private boolean get_mapping(String line) {

    mappingResult = line;
    StringBuilder mappingBuilder = new StringBuilder();
    for (char cc : line.toCharArray()) {
      if (Character.isAlphabetic(cc)) {
        mappingBuilder.append(mapping.get(Character.toUpperCase(cc)));
      }
      else if (Character.isDigit(cc)) {
        mappingBuilder.append(cc);
      }
      else {
        return false;
      }
    }
    mappingResult = mappingBuilder.toString();

    return true;
  }

  public static void main(String[] args) {

    String filename;
    if (args.length > 0) {
      filename = args[0];
    }
    else {
      filename = "./unixdict.txt";
    }
    RTextonyms tc;
    tc = new RTextonyms(filename);
    Path fp = Paths.get(filename);
    try (Scanner fs = new Scanner(fp, StandardCharsets.UTF_8.name())) {
      while (fs.hasNextLine()) {
        tc.add(fs.nextLine());
      }
    }
    catch (IOException ex) {
      ex.printStackTrace();
    }

    List<String> numbers = Arrays.asList(
        "001", "228", "27484247", "7244967473642",
        "."
        );

    tc.results();
    for (String number : numbers) {
      if (number.equals(".")) {
        System.out.println();
      }
      else {
        tc.match(number);
      }
    }

    return;
  }
}

Output with "java RTextonyms ./unixdict.txt":

Read 25,104 words from ./unixdict.txt

There are 24,988 words in ./unixdict.txt which can be represented by the digit key mapping.
They require 22,905 digit combinations to represent them.
1,477 digit combinations represent Textonyms.
The numbers mapping to the most words map to 9 words each:
             269 maps to: [amy, any, bmw, bow, box, boy, cow, cox, coy]
             729 maps to: [paw, pax, pay, paz, raw, ray, saw, sax, say]

Key 001 not found
Key 228 matches: [aau, act, bat, cat]
Key 27484247 not found
Key 7244967473642 matches: [schizophrenia, schizophrenic]

jq

The following requires a version of jq with "gsub".

def textonym_value:
    gsub("a|b|c|A|B|C"; "2")
  | gsub("d|e|f|D|E|F"; "3")
  | gsub("g|h|i|G|H|I"; "4")
  | gsub("j|k|l|J|K|L"; "5")
  | gsub("m|n|o|M|N|O"; "6")
  | gsub("p|q|r|s|P|Q|R|S"; "7")
  | gsub("t|u|v|T|U|V"; "8")
  | gsub("w|x|y|z|W|X|Y|Z"; "9");

def explore:
  # given an array (or hash), find the maximum length of the items (or values):
  def max_length: [.[] | length] | max;

  # The length of the longest textonym in the dictionary of numericString => array:
  def longest:
    [to_entries[] | select(.value|length > 1) | .key | length] | max;

  # pretty-print a key-value pair:
  def pp: "\(.key) maps to: \(.value|tostring)";
  
  split("\n")
  | map(select(test("^[a-zA-Z]+$")))  # select the strictly alphabetic strings
  | length as $nwords
  | reduce .[] as $line
    ( {};
      ($line | textonym_value) as $key
      | .[$key] += [$line] )
  | max_length as $max_length
  | longest    as $longest
  | "There are \($nwords) words in the Textonyms/wordlist word list that can be represented by the digit-key mapping.",
    "They require \(length) digit combinations to represent them.",
    "\( [.[] | select(length>1) ] | length ) digit combinations represent Textonyms.",
    "The numbers mapping to the most words map to \($max_length) words:",
     (to_entries[] | select((.value|length) == $max_length) | pp ),
    "The longest Textonyms in the word list have length \($longest):",
     (to_entries[] | select((.key|length) == $longest and (.value|length > 1)) | pp)
;

explore

Output:

$ jq -R -r -c -s -f textonyms.jq textonyms.txt
There are 13085 words in the Textonyms/wordlist word list that can be represented by the digit-key mapping.
They require 11932 digit combinations to represent them.
661 digit combinations represent Textonyms.
The numbers mapping to the most words map to 15 words:
27 maps to: ["AP","AQ","AR","AS","Ar","As","BP","BR","BS","Br","CP","CQ","CR","Cr","Cs"]
The longest Textonyms in the word list have length 11:
26456746242 maps to: ["Anglophobia","Anglophobic"]
24636272673 maps to: ["CinemaScope","Cinemascope"]

This solution uses an aspell dictionary on the local machine as its word source. The character to number mapping is done via regular expressions and Julia's replace function. Because this list contains accented characters, the matching expressions were expanded to include such characters. Words are case sensitive, but the mapping is not, so for example both "Homer" and "homer" are included in the tabulation, each coded as "46637". Function

using Printf

const tcode = (Regex=>Char)[r"A|B|C|Ä|Å|Á|Â|Ç" => '2',
                            r"D|E|F|È|Ê|É" => '3',
                            r"G|H|I|Í" => '4',
                            r"J|K|L" => '5',
                            r"M|N|O|Ó|Ö|Ô|Ñ" => '6',
                            r"P|Q|R|S" => '7',
                            r"T|U|V|Û|Ü" => '8',
                            r"W|X|Y|Z" => '9']

function tpad(str::IOStream)
    tnym = (String=>Array{String,1})[]
    for w in eachline(str)
        w = chomp(w)
        t = uppercase(w)
        for (k,v) in tcode
            t = replace(t, k, v)
        end
        t = replace(t, r"\D", '1')
        tnym[t] = [get(tnym, t, String[]), w]
    end
    return tnym
end

Main

dname = "/usr/share/dict/american-english"
DF = open(dname, "r")
tnym = tpad(DF)
close(DF)

println("The character to digit mapping is done according to")
println("these regular expressions (following uppercase conversion):")
for k in sort(collect(keys(tcode)), by=x->tcode[x])
    println("    ", tcode[k], " -> ", k)
end
println("Unmatched non-digit characters are mapped to 1")

println()    
print("There are ", sum(map(x->length(x), values(tnym))))
println(" words in ", dname)
println("  which can be represented by the digit key mapping.")
print("They require ", length(keys(tnym)))
println(" digit combinations to represent them.")
print(sum(map(x->length(x)>1, values(tnym))))
println(" digit combinations represent Textonyms.")

println()
println("The degeneracies of telephone key encodings are:")
println("  Words Encoded   Number of codes")
dgen = zeros(maximum(map(x->length(x), values(tnym))))
for v in values(tnym)
    dgen[length(v)] += 1
end
for (i, d) in enumerate(dgen)
    println(@sprintf "%10d  %15d" i d)
end

println()
dgen = length(dgen) - 2
println("Codes mapping to ", dgen, " or more words:")
for (k, v) in tnym
    dgen <= length(v) || continue
    println(@sprintf "%7s (%2d) %s" k length(v) join(v, ", "))
end

Output:

The character to digit mapping is done according to
these regular expressions (following uppercase conversion):
    2 -> r"A|B|C|Ä|Å|Á|Â|Ç"
    3 -> r"D|E|F|È|Ê|É"
    4 -> r"G|H|I|Í"
    5 -> r"J|K|L"
    6 -> r"M|N|O|Ó|Ö|Ô|Ñ"
    7 -> r"P|Q|R|S"
    8 -> r"T|U|V|Û|Ü"
    9 -> r"W|X|Y|Z"
Unmatched non-digit characters are mapped to 1

There are 99171 words in /usr/share/dict/american-english
  which can be represented by the digit key mapping.
They require 89353 digit combinations to represent them.
6860 digit combinations represent Textonyms.

The degeneracies of telephone key encodings are:
  Words Encoded   Number of codes
         1            82493
         2             5088
         3             1104
         4              383
         5              159
         6               72
         7               24
         8               16
         9                8
        10                4
        11                1
        12                1

Codes mapping to 10 or more words:
    269 (11) Amy, BMW, Cox, Coy, any, bow, box, boy, cow, cox, coy
  22737 (12) acres, bards, barer, bares, barfs, baser, bases, caper, capes, cards, cares, cases
   2273 (10) Case, acre, bard, bare, barf, base, cape, card, care, case
  46637 (10) Homer, goner, goods, goofs, homer, homes, hones, hoods, hoofs, inner
   7217 (10) PA's, PC's, Pa's, Pb's, Ra's, Rb's, SC's, Sb's, Sc's, pa's
   4317 (10) GE's, Gd's, Ge's, HF's, He's, Hf's, ID's, he's, id's, if's

Kotlin

// version 1.1.4-3

import java.io.File

val wordList = "unixdict.txt"
val url = "http://www.puzzlers.org/pub/wordlists/unixdict.txt"

const val DIGITS = "22233344455566677778889999"

val map = mutableMapOf<String, MutableList<String>>()

fun processList() {
    var countValid = 0
    val f = File(wordList)
    val sb = StringBuilder()

    f.forEachLine { word->
        var valid = true
        sb.setLength(0)
        for (c in word.toLowerCase()) {
            if (c !in 'a'..'z') {
                valid = false
                break
            } 
            sb.append(DIGITS[c - 'a'])
        }
        if (valid) {
            countValid++
            val key = sb.toString()
            if (map.containsKey(key)) {
                map[key]!!.add(word)
            }
            else {
                map.put(key, mutableListOf(word))
            }
        }    
    }
    var textonyms = map.filter { it.value.size > 1 }.toList() 
    val report = "There are $countValid words in '$url' " +
                 "which can be represented by the digit key mapping.\n" +
                 "They require ${map.size} digit combinations to represent them.\n" +
                 "${textonyms.size} digit combinations represent Textonyms.\n"
    println(report)

    val longest = textonyms.sortedByDescending { it.first.length }
    val ambiguous = longest.sortedByDescending { it.second.size }

    println("Top 8 in ambiguity:\n")
    println("Count   Textonym  Words")
    println("======  ========  =====")
    var fmt = "%4d    %-8s  %s"
    for (a in ambiguous.take(8)) println(fmt.format(a.second.size, a.first, a.second))

    fmt = fmt.replace("8", "14")
    println("\nTop 6 in length:\n")
    println("Length  Textonym        Words")
    println("======  ==============  =====")
    for (l in longest.take(6)) println(fmt.format(l.first.length, l.first, l.second))           
}

fun main(args: Array<String>) {
    processList()
}

Output:

There are 24978 words in 'http://www.puzzlers.org/pub/wordlists/unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 8 in ambiguity:

Count   Textonym  Words
======  ========  =====
   9    269       [amy, any, bmw, bow, box, boy, cow, cox, coy]
   9    729       [paw, pax, pay, paz, raw, ray, saw, sax, say]
   8    2273      [acre, bard, bare, base, cape, card, care, case]
   8    726       [pam, pan, ram, ran, sam, san, sao, scm]
   7    4663      [gone, good, goof, home, hone, hood, hoof]
   7    7283      [pate, pave, rate, rave, saud, save, scud]
   7    426       [gam, gao, ham, han, ian, ibm, ibn]
   7    782       [pta, pub, puc, pvc, qua, rub, sub]

Top 6 in length:

Length  Textonym        Words
======  ==============  =====
  14    25287876746242  [claustrophobia, claustrophobic]
  13    7244967473642   [schizophrenia, schizophrenic]
  12    666628676342    [onomatopoeia, onomatopoeic]
  11    49376746242     [hydrophobia, hydrophobic]
  10    2668368466      [contention, convention]
  10    6388537663      [mettlesome, nettlesome]

Lua

-- Global variables
http = require("socket.http")
keys = {"VOICEMAIL", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"}
dictFile = "http://www.puzzlers.org/pub/wordlists/unixdict.txt"

-- Return the sequence of keys required to type a given word
function keySequence (str)
    local sequence, noMatch, letter = ""
    for pos = 1, #str do
        letter = str:sub(pos, pos)
        for i, chars in pairs(keys) do
            noMatch = true
            if chars:match(letter) then
                sequence = sequence .. tostring(i)
                noMatch = false
                break
            end
        end
        if noMatch then return nil end
    end
    return tonumber(sequence)
end

-- Generate table of words grouped by key sequence
function textonyms (dict)
    local combTable, keySeq = {}
    for word in dict:gmatch("%S+") do
        keySeq = keySequence(word)
        if keySeq then
            if combTable[keySeq] then
                table.insert(combTable[keySeq], word)
            else
                combTable[keySeq] = {word}
            end
        end
    end
    return combTable
end

-- Analyse sequence table and print details
function showReport (keySeqs)
    local wordCount, seqCount, tCount = 0, 0, 0
    for seq, wordList in pairs(keySeqs) do
        wordCount = wordCount + #wordList
        seqCount = seqCount + 1
        if #wordList > 1 then tCount = tCount + 1 end
    end
    print("There are " .. wordCount .. " words in " .. dictFile)
    print("which can be represented by the digit key mapping.")
    print("They require " .. seqCount .. " digit combinations to represent them.")
    print(tCount .. " digit combinations represent Textonyms.")
end

-- Main procedure
showReport(textonyms(http.request(dictFile)))

Output:

There are 24983 words in http://www.puzzlers.org/pub/wordlists/unixdict.txt
which can be represented by the digit key mapping.
They require 22908 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Mathematica /Wolfram Language

ClearAll[Numerify,rls]
rls={"A"->2,"B"->2,"C"->2,"D"->3,"E"->3,"F"->3,"G"->4,"H"->4,"I"->4,"J"->5,"K"->5,"L"->5,"M"->6,"N"->6,"O"->6,"P"->7,"Q"->7,"R"->7,"S"->7,"T"->8,"U"->8,"V"->8,"W"->9,"X"->9,"Y"->9,"Z"->9};
Numerify[s_String]:=Characters[ToUpperCase[s]]/.rls
dict=Once[Import["http://www.rosettacode.org/wiki/Textonyms/wordlist","XML"]];
dict=Cases[dict,XMLElement["pre",{},{x_}]:>x,\[Infinity]];
dict=TakeLargestBy[dict,ByteCount,1][[1]];
dict=DeleteDuplicates[StringTrim/*ToUpperCase/@StringSplit[dict]];
dict=Select[dict,StringMatchQ[(Alternatives@@Keys[rls])..]];
Print["Number of words from Textonyms/wordlist are: ",Length[dict]]
grouped=GroupBy[dict[[;;;;10]],Numerify];
Print["Number of unique numbers: ",Length[grouped]]
grouped=Select[grouped,Length/*GreaterThan[1]];
Print["Most with the same number:"]
KeyValueMap[List,TakeLargestBy[grouped,Length,1]]//Grid
Print["5 longest words with textonyms:"]
List@@@Normal[ReverseSortBy[grouped,First/*Length][[;;5]]]//Grid

Output:

Number of words from Textonyms/wordlist are: 71125
Number of unique numbers: 7030
Most with the same number:
{2,6,6,6}	{AMON,COMO,CONN,ANON}
5 longest words with textonyms:
{2,4,6,6,4,7,4,6,4}	{CHONGQING,AGONISING}
{3,5,3,2,8,4,6,6}	{EJECTION,ELECTION}
{2,8,7,8,4,3,7,8}	{BUSTIEST,CURVIEST}
{2,8,7,3,8,8,3,7}	{BURETTES,CURETTES}
{3,7,8,2,8,3,7}	{EQUATES,ESTATES}

MiniScript

This solution assumes the Mini Micro environment (providing the listUtil and mapUtil modules, as well as the englishWords.txt file).

import "listUtil"
import "mapUtil"

groups = "abc def ghi jkl mno pqrs tuv wxyz".split
charToNum = {}
for i in groups.indexes
	for ch in groups[i]
		charToNum[ch] = i + 2
	end for
end for

words = file.readLines("/sys/data/englishWords.txt")

wordToNum = function(word)
	parts = word.split("")
	parts.apply function(ch)
		return charToNum[ch]
	end function
	return parts.join("")
end function

numToWords = {}
moreThan1Word = 0
for word in words
	num = wordToNum(word.lower)
	if numToWords.hasIndex(num) then
		numToWords[num].push word
	else
		numToWords[num] = [word]
	end if
	if numToWords[num].len == 2 then moreThan1Word = moreThan1Word + 1
end for

print "There are " + words.len + " words in englishWords.txt which can be represented  by the digit key mapping."
print "They require " + numToWords.len + " digit combinations to represent them."
print moreThan1Word + " digit combinations represent Textonyms."

while true
	print
	inp = input("Enter a word or digit combination: ")
	if not inp then break
	if val(inp) > 0 then
		print inp + " -> " + numToWords.get(inp)
	else
		num = wordToNum(inp.lower)
		print "Digit key combination for """ + inp + """ is: " + num
		print num + " -> " + numToWords.get(num)
	end if
end while

Output:

There are 64664 words in englishWords.txt which can be represented
by the digit key mapping.
They require 59148 digit combinations to represent them.
4028 digit combinations represent Textonyms.

Enter a word or digit combination: 2877464
2877464 -> ["burping", "bussing", "cupping", "cursing", "cussing"]

Enter a word or digit combination: phoning
Digit key combination for "phoning" is: 7466464
7466464 -> ["phoning", "pinning", "rimming", "shooing", "sinning"]

Nim

Translation of: Kotlin

import algorithm, sequtils, strformat, strutils, tables

const

  WordList = "unixdict.txt"
  Url = "http://www.puzzlers.org/pub/wordlists/unixdict.txt"

  Digits = "22233344455566677778889999"

proc processList(wordFile: string) =

  var mapping: Table[string, seq[string]]
  var countValid = 0

  for word in wordFile.lines:
    var valid = true
    var key: string
    for c in word.toLowerAscii:
      if c notin 'a'..'z':
        valid = false
        break
      key.add Digits[ord(c) - ord('a')]
    if valid:
      inc countValid
      mapping.mgetOrPut(key, @[]).add word

  let textonyms = toSeq(mapping.pairs).filterIt(it[1].len > 1)
  echo &"There are {countValid} words in '{Url}' ",
       &"which can be represented by the digit key mapping."
  echo &"They require {mapping.len} digit combinations to represent them."
  echo &"{textonyms.len} digit combinations represent Textonyms.\n"

  let longest = textonyms.sortedByIt(-it[0].len)
  let ambiguous = longest.sortedByIt(-it[1].len)
  echo "Top 8 in ambiguity:\n"
  echo "Count   Textonym  Words"
  echo "======  ========  ====="
  for a in ambiguous[0..7]:
    echo &"""{a[1].len:4}    {a[0]:>8}  {a[1].join(", ")}"""

  echo "\nTop 6 in length:\n"
  echo "Length  Textonym        Words"
  echo "======  ==============  ====="
  for l in longest[0..5]:
    echo &"""{l[0].len:4}    {l[0]:>14}  {l[1].join(", ")}"""

processList(WordList)

Output:

There are 24978 words in 'http://www.puzzlers.org/pub/wordlists/unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 8 in ambiguity:

Count   Textonym  Words
======  ========  =====
   9         729  paw, pax, pay, paz, raw, ray, saw, sax, say
   9         269  amy, any, bmw, bow, box, boy, cow, cox, coy
   8        2273  acre, bard, bare, base, cape, card, care, case
   8         726  pam, pan, ram, ran, sam, san, sao, scm
   7        4663  gone, good, goof, home, hone, hood, hoof
   7        7283  pate, pave, rate, rave, saud, save, scud
   7         782  pta, pub, puc, pvc, qua, rub, sub
   7         426  gam, gao, ham, han, ian, ibm, ibn

Top 6 in length:

Length  Textonym        Words
======  ==============  =====
  14    25287876746242  claustrophobia, claustrophobic
  13     7244967473642  schizophrenia, schizophrenic
  12      666628676342  onomatopoeia, onomatopoeic
  11       49376746242  hydrophobia, hydrophobic
  10        2668368466  contention, convention
  10        6388537663  mettlesome, nettlesome

OCaml

module IntMap = Map.Make(Int)

let seq_lines ch =
  let rec repeat () =
    match input_line ch with
    | s -> Seq.Cons (s, repeat)
    | exception End_of_file -> Nil
  in repeat

(* simply use bijective numeration in base 8 for keys *)

let key_of_char = function
  | 'a' .. 'c' -> Some 1
  | 'd' .. 'f' -> Some 2
  | 'g' .. 'i' -> Some 3
  | 'j' .. 'l' -> Some 4
  | 'm' .. 'o' -> Some 5
  | 'p' .. 's' -> Some 6
  | 't' .. 'v' -> Some 7
  | 'w' .. 'z' -> Some 8
  | _ -> None

let keys_of_word =
  let next k c =
    Option.bind (key_of_char c) (fun d -> Option.map (fun k -> k lsl 3 + d) k)
  in String.fold_left next (Some 0)

let update m k =
  IntMap.update k (function Some n -> Some (succ n) | None -> Some 1) m

let map_from ch =
  seq_lines ch |> Seq.filter_map keys_of_word |> Seq.fold_left update IntMap.empty

let count _ n (words, keys, txtns) =
  words + n, succ keys, if n > 1 then succ txtns else txtns

let show src (words, keys, txtns) = Printf.printf "\
  There are %u words in %s which can be represented by the digit key mapping.\n\
  They require %u digit combinations to represent them.\n\
  %u digit combinations represent Textonyms.\n" words src keys txtns

let () =
  show "stdin" (IntMap.fold count (map_from stdin) (0, 0, 0))

Output:

There are 24978 words in stdin which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

...when being feeded with unixdict.txt

Perl

my $src = 'unixdict.txt';

# filter word-file for valid input, transform to low-case 
open $fh, "<", $src;
@words = grep { /^[a-zA-Z]+$/ } <$fh>;
map { tr/A-Z/a-z/ } @words;

# translate words to dials
map { tr/abcdefghijklmnopqrstuvwxyz/22233344455566677778889999/ } @dials = @words;

# get unique values (modify @dials) and non-unique ones (are textonyms)
@dials = grep {!$h{$_}++} @dials;
@textonyms = grep { $h{$_} > 1 } @dials;

print "There are @{[scalar @words]} words in '$src' which can be represented by the digit key mapping.
They require @{[scalar @dials]} digit combinations to represent them.
@{[scalar @textonyms]} digit combinations represent Textonyms.";

Output:

There are 24978 words in 'unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Phix

with javascript_semantics
sequence digit = repeat(-1,255)
         digit['a'..'c'] = '2'
         digit['d'..'f'] = '3'
         digit['g'..'i'] = '4'
         digit['j'..'l'] = '5'
         digit['m'..'o'] = '6'
         digit['p'..'s'] = '7'
         digit['t'..'v'] = '8'
         digit['w'..'z'] = '9'
 
function digits(string word)
    string keycode = repeat(' ',length(word))
    for i=1 to length(word) do
        integer ch = word[i]
        assert(ch>='a' and ch<='z')
        keycode[i] = digit[ch]
    end for
    return {keycode,word}
end function

function az(string word) return min(word)>='a' and max(word)<='z' end function
 
sequence words = apply(filter(unix_dict(),az),digits), max_idx, long_idx
string word, keycode, last = ""
integer keycode_count = 0, textonyms = 0, 
        this_count = 0, max_count = 0, longest = 0
 
printf(1,"There are %d words in unixdict.txt which can be represented by the digit key mapping.\n",{length(words)})
 
-- Sort by keycode: while words are ordered we get
--  eg {"a","ab","b","ba"} -> {"2","22","2","22"}
words = sort(deep_copy(words))

for i=1 to length(words) do
    {keycode,word} = words[i]
    if keycode=last then
        textonyms += this_count=1
        this_count += 1
        if this_count>=max_count then
            if this_count>max_count then
                max_idx = {i}
            else
                max_idx &= i
            end if
            max_count = this_count
        end if
    else
        keycode_count += 1
        last = keycode
        this_count = 1
    end if
    if length(word)>=longest then
        if length(word)>longest then
            long_idx = {i}
        else
            long_idx &= i
        end if
        longest = length(word)
    end if
end for
printf(1,"They require %d digit combinations to represent them.\n",{keycode_count})
printf(1,"%d digit combinations represent Textonyms.\n",{textonyms})
printf(1,"The maximum number of textonyms for a particular digit key mapping is %d:\n",{max_count})
for i=1 to length(max_idx) do
    integer k = max_idx[i], l = k-max_count+1
    string dups = join(vslice(words[l..k],2),"/")
    printf(1," %s encodes %s\n",{words[k][1],dups})
end for
printf(1,"The longest words are %d characters long\n",longest)
printf(1,"Encodings with this length are:\n")
for i=1 to length(long_idx) do
    printf(1,"   %s encodes %s\n",words[long_idx[i]])
end for

Output:

(my unixdict.txt seems to have grown by 4 entries sometime in the past couple of years...)

There are 24981 words in unixdict.txt which can be represented by the digit key mapping.
They require 22906 digit combinations to represent them.
1473 digit combinations represent Textonyms.
The maximum number of textonyms for a particular digit key mapping is 9:
 269 encodes amy/any/bmw/bow/box/boy/cow/cox/coy
 729 encodes paw/pax/pay/paz/raw/ray/saw/sax/say
The longest words are 22 characters long
Encodings with this length are:
   3532876362374256472749 encodes electroencephalography

PowerShell

$url  = "http://www.puzzlers.org/pub/wordlists/unixdict.txt"
$file = "$env:TEMP\unixdict.txt"
(New-Object System.Net.WebClient).DownloadFile($url, $file)
$unixdict = Get-Content -Path $file

[string]$alpha = "abcdefghijklmnopqrstuvwxyz"
[string]$digit = "22233344455566677778889999"

$table = [ordered]@{}

for ($i = 0; $i -lt $alpha.Length; $i++)
{ 
    $table.Add($alpha[$i], $digit[$i])
}

$words = foreach ($word in $unixdict)
{
    if ($word -match "^[a-z]*$")
    {
        [PSCustomObject]@{
            Word   = $word
            Number = ($word.ToCharArray() | ForEach-Object {$table.$_}) -join ""
        }
    }
}

$digitCombinations = $words | Group-Object -Property Number

$textonyms = $digitCombinations | Where-Object -Property Count -GT 1 | Sort-Object -Property Count -Descending

Write-Host ("There are {0} words in {1} which can be represented by the digit key mapping." -f $words.Count, $url)
Write-Host ("They require {0} digit combinations to represent them."                        -f $digitCombinations.Count)
Write-Host ("{0} digit combinations represent Textonyms.`n"                                 -f $textonyms.Count)

Write-Host "Top 5 in ambiguity:"
$textonyms | Select-Object -First 5 -Property Count,
                                              @{Name="Textonym"; Expression={$_.Name}},
                                              @{Name="Words"   ; Expression={$_.Group.Word -join ", "}} | Format-Table -AutoSize
Write-Host "Top 5 in length:"
$textonyms | Sort-Object {$_.Name.Length} -Descending |
             Select-Object -First 5 -Property @{Name="Length"  ; Expression={$_.Name.Length}},
                                              @{Name="Textonym"; Expression={$_.Name}},
                                              @{Name="Words"   ; Expression={$_.Group.Word -join ", "}} | Format-Table -AutoSize

Remove-Item -Path $file -Force -ErrorAction SilentlyContinue

Output:

There are 24978 words in http://www.puzzlers.org/pub/wordlists/unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 in ambiguity:

Count Textonym Words                                         
----- -------- -----                                         
    9 729      paw, pax, pay, paz, raw, ray, saw, sax, say   
    9 269      amy, any, bmw, bow, box, boy, cow, cox, coy   
    8 726      pam, pan, ram, ran, sam, san, sao, scm        
    8 2273     acre, bard, bare, base, cape, card, care, case
    7 426      gam, gao, ham, han, ian, ibm, ibn             


Top 5 in length:

Length Textonym       Words                         
------ --------       -----                         
    14 25287876746242 claustrophobia, claustrophobic
    13 7244967473642  schizophrenia, schizophrenic  
    12 666628676342   onomatopoeia, onomatopoeic    
    11 49376746242    hydrophobia, hydrophobic      
    10 6388537663     mettlesome, nettlesome

Python

from collections import defaultdict
import urllib.request

CH2NUM = {ch: str(num) for num, chars in enumerate('abc def ghi jkl mno pqrs tuv wxyz'.split(), 2) for ch in chars}
URL = 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'


def getwords(url):
 return urllib.request.urlopen(url).read().decode("utf-8").lower().split()

def mapnum2words(words):
    number2words = defaultdict(list)
    reject = 0
    for word in words:
        try:
            number2words[''.join(CH2NUM[ch] for ch in word)].append(word)
        except KeyError:
            # Reject words with non a-z e.g. '10th'
            reject += 1
    return dict(number2words), reject

def interactiveconversions():
    global inp, ch, num
    while True:
        inp = input("\nType a number or a word to get the translation and textonyms: ").strip().lower()
        if inp:
            if all(ch in '23456789' for ch in inp):
                if inp in num2words:
                    print("  Number {0} has the following textonyms in the dictionary: {1}".format(inp, ', '.join(
                        num2words[inp])))
                else:
                    print("  Number {0} has no textonyms in the dictionary.".format(inp))
            elif all(ch in CH2NUM for ch in inp):
                num = ''.join(CH2NUM[ch] for ch in inp)
                print("  Word {0} is{1} in the dictionary and is number {2} with textonyms: {3}".format(
                    inp, ('' if inp in wordset else "n't"), num, ', '.join(num2words[num])))
            else:
                print("  I don't understand %r" % inp)
        else:
            print("Thank you")
            break


if __name__ == '__main__':
    words = getwords(URL)
    print("Read %i words from %r" % (len(words), URL))
    wordset = set(words)
    num2words, reject = mapnum2words(words)
    morethan1word = sum(1 for w in num2words if len(num2words[w]) > 1)
    maxwordpernum = max(len(values) for values in num2words.values())
    print("""
There are {0} words in {1} which can be represented by the Textonyms mapping.
They require {2} digit combinations to represent them.
{3} digit combinations represent Textonyms.\
""".format(len(words) - reject, URL, len(num2words), morethan1word))

    print("\nThe numbers mapping to the most words map to %i words each:" % maxwordpernum)
    maxwpn = sorted((key, val) for key, val in num2words.items() if len(val) == maxwordpernum)
    for num, wrds in maxwpn:
        print("  %s maps to: %s" % (num, ', '.join(wrds)))

    interactiveconversions()

Output:

Read 25104 words from 'http://www.puzzlers.org/pub/wordlists/unixdict.txt'

There are 24978 words in http://www.puzzlers.org/pub/wordlists/unixdict.txt which can be represented by the Textonyms mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

The numbers mapping to the most words map to 9 words each:
  269 maps to: amy, any, bmw, bow, box, boy, cow, cox, coy
  729 maps to: paw, pax, pay, paz, raw, ray, saw, sax, say

Type a number or a word to get the translation and textonyms: rosetta
  Word rosetta is in the dictionary and is number 7673882 with textonyms: rosetta

Type a number or a word to get the translation and textonyms: code
  Word code is in the dictionary and is number 2633 with textonyms: bode, code, coed

Type a number or a word to get the translation and textonyms: 2468
  Number 2468 has the following textonyms in the dictionary: ainu, chou

Type a number or a word to get the translation and textonyms: 3579
  Number 3579 has no textonyms in the dictionary.

Type a number or a word to get the translation and textonyms: 
Thank you

Racket

This version allows digits to be used (since you can usually enter them through an SMS-style keypad).

unixdict.txt has words like 2nd which would not be valid using letters only, but is textable.

#lang racket
(module+ test (require tests/eli-tester))
(module+ test
  (test
   (map char->sms-digit (string->list "ABCDEFGHIJKLMNOPQRSTUVWXYZ."))
   => (list 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 7 8 8 8 9 9 9 9 #f)))

(define char->sms-digit
  (match-lambda
    [(? char-lower-case? (app char-upcase C)) (char->sms-digit C)]
    ;; Digits, too, can be entered on a text pad!
    [(? char-numeric? (app char->integer c)) (- c (char->integer #\0))]
    [(or #\A #\B #\C) 2]
    [(or #\D #\E #\F) 3]
    [(or #\G #\H #\I) 4]
    [(or #\J #\K #\L) 5]
    [(or #\M #\N #\O) 6]
    [(or #\P #\Q #\R #\S) 7]
    [(or #\T #\U #\V) 8]
    [(or #\W #\X #\Y #\Z) 9]
    [_ #f]))

(module+ test
  (test
   (word->textonym "criticisms") => 2748424767
   (word->textonym "Briticisms") => 2748424767
   (= (word->textonym "Briticisms") (word->textonym "criticisms"))))

(define (word->textonym w)
  (for/fold ((n 0)) ((s (sequence-map char->sms-digit (in-string w))) #:final (not s))
    (and s (+ (* n 10) s))))

(module+ test
  (test
   ((cons-uniquely 'a) null) => '(a)
   ((cons-uniquely 'a) '(b)) => '(a b)
   ((cons-uniquely 'a) '(a b c)) => '(a b c)))

(define ((cons-uniquely a) d)
  (if (member a d) d (cons a d)))

(module+ test
  (test
   (with-input-from-string "criticisms" port->textonym#) =>
   (values 1 (hash 2748424767 '("criticisms")))
   (with-input-from-string "criticisms\nBriticisms" port->textonym#) =>
   (values 2 (hash 2748424767 '("Briticisms" "criticisms")))
   (with-input-from-string "oh-no!-dashes" port->textonym#) =>
   (values 0 (hash))))

(define (port->textonym#)
  (for/fold
   ((n 0) (t# (hash)))
   ((w (in-port read-line)))
    (define s (word->textonym w))
    (if s
        (values (+ n 1) (hash-update t# s (cons-uniquely w) null))
        (values n t#))))

(define (report-on-file f-name)
  (define-values (n-words textonym#) (with-input-from-file f-name port->textonym#))
  
  (define n-textonyms (for/sum ((v (in-hash-values textonym#)) #:when (> (length v) 1)) 1))
  
  (printf "--- report on ~s ends ---~%" f-name)
  (printf
   #<<EOS
There are ~a words in ~s which can be represented by the digit key mapping.
They require ~a digit combinations to represent them.
~a digit combinations represent Textonyms.

EOS
   n-words f-name (hash-count textonym#) n-textonyms)
  
  ;; Show all the 6+ textonyms
  (newline)
  (for (((k v) (in-hash textonym#)) #:when (>= (length v) 6)) (printf "~a -> ~s~%" k v))
  (printf "--- report on ~s ends ---~%" f-name))

(module+ main
  (report-on-file "data/unixdict.txt"))

Output:

--- report on "data/unixdict.txt" ends ---
There are 24988 words in "data/unixdict.txt" which can be represented by the digit key mapping.
They require 22905 digit combinations to represent them.
1477 digit combinations represent Textonyms.

226 -> ("can" "cam" "ban" "bam" "acm" "abo")
269 -> ("coy" "cox" "cow" "boy" "box" "bow" "bmw" "any" "amy")
426 -> ("ibn" "ibm" "ian" "han" "ham" "gao" "gam")
529 -> ("lay" "lax" "law" "kay" "jay" "jaw")
627 -> ("oar" "ncr" "nbs" "nap" "mar" "map")
729 -> ("say" "sax" "saw" "ray" "raw" "paz" "pay" "pax" "paw")
726 -> ("scm" "sao" "san" "sam" "ran" "ram" "pan" "pam")
782 -> ("sub" "rub" "qua" "pvc" "puc" "pub" "pta")
786 -> ("sun" "sum" "run" "rum" "quo" "pun")
843 -> ("vie" "vhf" "uhf" "tie" "tid" "the")
2273 -> ("case" "care" "card" "cape" "base" "bare" "bard" "acre")
2253 -> ("calf" "cake" "bale" "bald" "bake" "able")
2666 -> ("coon" "conn" "boon" "boom" "bonn" "ammo")
4663 -> ("hoof" "hood" "hone" "home" "goof" "good" "gone")
7283 -> ("scud" "save" "saud" "rave" "rate" "pave" "pate")
7243 -> ("said" "sage" "raid" "rage" "paid" "page")
7325 -> ("seal" "reck" "real" "peck" "peal" "peak")
7673 -> ("sore" "rose" "rope" "pose" "pore" "pope")
--- report on "data/unixdict.txt" ends ---
1 test passed
3 tests passed
3 tests passed
3 tests passed

Raku

(formerly Perl 6)

my $src = 'unixdict.txt';

my @words = slurp($src).lines.grep(/ ^ <alpha>+ $ /);

my @dials = @words.classify: {
    .trans('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
        => '2223334445556667777888999922233344455566677778889999');
}

my @textonyms = @dials.grep(*.value > 1);

say qq:to 'END';
    There are {+@words} words in $src which can be represented by the digit key mapping.
    They require {+@dials} digit combinations to represent them.
    {+@textonyms} digit combinations represent Textonyms.
    END

say "Top 5 in ambiguity:";
say "    ",$_ for @textonyms.sort(-*.value)[^5];

say "\nTop 5 in length:";
say "    ",$_ for @textonyms.sort(-*.key.chars)[^5];

Output:

There are 24978 words in unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 in ambiguity:
    269 => amy any bmw bow box boy cow cox coy
    729 => paw pax pay paz raw ray saw sax say
    2273 => acre bard bare base cape card care case
    726 => pam pan ram ran sam san sao scm
    426 => gam gao ham han ian ibm ibn

Top 5 in length:
    25287876746242 => claustrophobia claustrophobic
    7244967473642 => schizophrenia schizophrenic
    666628676342 => onomatopoeia onomatopoeic
    49376746242 => hydrophobia hydrophobic
    2668368466 => contention convention

REXX

Extra code was added detect and display a count illegal words (words not representable by the key digits), and
also duplicate words in the dictionary.

/*REXX program counts and displays the number of textonyms that are in a dictionary file*/
parse arg iFID .                                 /*obtain optional fileID from the C.L. */
if iFID=='' | iFID=="," then iFID='UNIXDICT.TXT' /*Not specified?  Then use the default.*/
@.= 0                                            /*the placeholder of digit combinations*/
!.=;       $.=                                   /*sparse array of textonyms;  words.   */
alphabet= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'           /*the supported alphabet to be used.   */
digitKey=  22233344455566677778889999            /*translated alphabet to digit keys.   */
digKey= 0;                 #word= 0              /*number digit combinations; word count*/
ills= 0 ;    dups= 0;    longest= 0;   mostus= 0 /*illegals; duplicated words; longest..*/
first=. ;    last= .;       long= 0;   most=   0 /*first, last, longest, most counts.   */
call linein  iFID, 1, 0                          /*point to the first char in dictionary*/
#= 0                                             /*number of textonyms in file (so far).*/

  do while  lines(iFID)\==0;     x= linein(iFID) /*keep reading the file until exhausted*/
  y= x;     upper x                              /*save a copy of  X;    uppercase  X.  */
  if \datatype(x, 'U')  then do;  ills= ills + 1;  iterate;  end     /*Not legal?  Skip.*/
  if $.x==.             then do;  dups= dups + 1;  iterate;  end     /*Duplicate?  Skip.*/
  $.x= .                                         /*indicate that it's a righteous word. */
  #word= #word + 1                               /*bump the word count  (for the file). */
  z= translate(x, digitKey, alphabet)            /*build a translated digit key word.   */
  @.z= @.z + 1                                   /*flag that the digit key word exists. */
  !.z= !.z  y;        _= words(!.z)              /*build list of equivalent digit key(s)*/

  if _>most  then do; mostus= z;  most= _;  end  /*remember the  "mostus"  digit keys.  */

  if @.z==2  then do; #= # + 1                   /*bump the count of the  textonyms.    */
                      if first==.   then first=z /*the first textonym found.            */
                      last= z                    /* "   last     "      "               */
                      _= length(!.z)             /*the length (# chars) of the digit key*/
                      if _>longest  then long= z /*is this the  longest  textonym ?     */
                      longest= max(_, longest)   /*now, use this length as a target/goal*/
                  end                            /* [↑]  discretionary  (extra credit). */

  if @.z==1  then digKey= digKey + 1             /*bump the count of digit key words.   */
  end   /*while*/

@dict= 'in the dictionary file'                  /*literal used for some displayed text.*/
L= length(commas(max(#word,ills,dups,digKey,#))) /*find length of max # being displayed.*/
say 'The dictionary file being used is: '   iFID
say
                call tell #word,  'words'                                           @dict,
                                  "which can be represented by digit key mapping"
if ills>0  then call tell ills,   'word's(ills)  "that contain illegal characters"  @dict
if dups>0  then call tell dups,   'duplicate word's(dups)  "detected"               @dict
                call tell digKey, 'combination's(digKey)   "required to represent them"
                call tell      #, 'digit combination's(#)  "that can represent Textonyms"
say
if first \== .  then say '    first digit key='   !.first
if  last \== .  then say '     last digit key='   !.last
if  long \== 0  then say '  longest digit key='   !.long
if  most \== 0  then say ' numerous digit key='   !.mostus   " ("most   'words)'
exit #                                           /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
commas: parse arg _;  do jc=length(_)-3  to 1  by -3; _=insert(',', _, jc); end;  return _
tell:   arg ##; say 'There are ' right(commas(##), L)' ' arg(2).; return   /*commatize #*/
s:      if arg(1)==1  then return '';      return "s"             /*a simple pluralizer.*/

output when using the default input file:

The dictionary file being used is:  UNIXDICT.TXT

There are  24,978  words in the dictionary file which can be represented by digit key mapping.
There are     126  words that contain illegal characters in the dictionary file.
There are  22,903  combinations required to represent them.
There are   1,473  digit combinations that can represent Textonyms.

    first digit key=  aaa aba abc cab
     last digit key=  woe zoe
  longest digit key=  claustrophobia claustrophobic
 numerous digit key=  amy any bmw bow box boy cow cox coy  (9 words)

output when using the input file: textonyms.txt

The dictionary file being used is:  TEXTONYMS.TXT

There are  12,990  words in the dictionary file which can be represented by digit key mapping.
There are      95  duplicate words detected in the dictionary file.
There are  11,932  combinations required to represent them.
There are     650  digit combinations that can represent Textonyms.

    first digit key=  AA AB AC BA BB BC CA CB
     last digit key=  Phillip Phillis
  longest digit key=  Anglophobia Anglophobic
 numerous digit key=  AP AQ AR AS BP BR BS CP CQ CR Cs  (11 words)

Ruby

CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
NUMS  = "22233344455566677778889999" * 2
dict  = "unixdict.txt"

textonyms = File.open(dict){|f| f.map(&:chomp).group_by {|word| word.tr(CHARS, NUMS) } }

puts "There are #{File.readlines(dict).size} words in #{dict} which can be represented by the digit key mapping.
They require #{textonyms.size} digit combinations to represent them.
#{textonyms.count{|_,v| v.size > 1}} digit combinations represent Textonyms."

puts "\n25287876746242: #{textonyms["25287876746242"].join(", ")}"

Output:

There are 25104 words in unixdict.txt which can be represented by the digit key mapping.
They require 23003 digit combinations to represent them.
1485 digit combinations represent Textonyms.

25287876746242: claustrophobia, claustrophobic

Rust

use std::collections::HashMap;
use std::fs::File;
use std::io::{self, BufRead};

fn text_char(ch: char) -> Option<char> {
    match ch {
        'a' | 'b' | 'c' => Some('2'),
        'd' | 'e' | 'f' => Some('3'),
        'g' | 'h' | 'i' => Some('4'),
        'j' | 'k' | 'l' => Some('5'),
        'm' | 'n' | 'o' => Some('6'),
        'p' | 'q' | 'r' | 's' => Some('7'),
        't' | 'u' | 'v' => Some('8'),
        'w' | 'x' | 'y' | 'z' => Some('9'),
        _ => None,
    }
}

fn text_string(s: &str) -> Option<String> {
    let mut text = String::with_capacity(s.len());
    for c in s.chars() {
        if let Some(t) = text_char(c) {
            text.push(t);
        } else {
            return None;
        }
    }
    Some(text)
}

fn print_top_words(textonyms: &Vec<(&String, &Vec<String>)>, top: usize) {
    for (text, words) in textonyms.iter().take(top) {
        println!("{} = {}", text, words.join(", "));
    }
}

fn find_textonyms(filename: &str) -> std::io::Result<()> {
    let file = File::open(filename)?;
    let mut table = HashMap::new();
    let mut count = 0;

    for line in io::BufReader::new(file).lines() {
        let mut word = line?;
        word.make_ascii_lowercase();
        if let Some(text) = text_string(&word) {
            let words = table.entry(text).or_insert(Vec::new());
            words.push(word);
            count += 1;
        }
    }

    let mut textonyms: Vec<(&String, &Vec<String>)> =
        table.iter().filter(|x| x.1.len() > 1).collect();

    println!(
        "There are {} words in '{}' which can be represented by the digit key mapping.",
        count, filename
    );
    println!(
        "They require {} digit combinations to represent them.",
        table.len()
    );
    println!(
        "{} digit combinations represent Textonyms.",
        textonyms.len()
    );

    let top = std::cmp::min(5, textonyms.len());
    textonyms.sort_by_key(|x| (std::cmp::Reverse(x.1.len()), x.0));
    println!("\nTop {} by number of words:", top);
    print_top_words(&textonyms, top);

    textonyms.sort_by_key(|x| (std::cmp::Reverse(x.0.len()), x.0));
    println!("\nTop {} by length:", top);
    print_top_words(&textonyms, top);

    Ok(())
}

fn main() {
    let args: Vec<String> = std::env::args().collect();
    if args.len() != 2 {
        eprintln!("usage: {} word-list", args[0]);
        std::process::exit(1);
    }
    match find_textonyms(&args[1]) {
        Ok(()) => {}
        Err(error) => eprintln!("{}: {}", args[1], error),
    }
}

Output:

There are 24978 words in 'unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 by number of words:
269 = amy, any, bmw, bow, box, boy, cow, cox, coy
729 = paw, pax, pay, paz, raw, ray, saw, sax, say
2273 = acre, bard, bare, base, cape, card, care, case
726 = pam, pan, ram, ran, sam, san, sao, scm
426 = gam, gao, ham, han, ian, ibm, ibn

Top 5 by length:
25287876746242 = claustrophobia, claustrophobic
7244967473642 = schizophrenia, schizophrenic
666628676342 = onomatopoeia, onomatopoeic
49376746242 = hydrophobia, hydrophobic
2668368466 = contention, convention

Sidef

Translation of: Raku

var words = ARGF.grep(/^[[:alpha:]]+\z/);

var dials = words.group_by {
    .tr('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
        '2223334445556667777888999922233344455566677778889999');
}

var textonyms = dials.grep_v { .len > 1 };

say <<-END;
    There are #{words.len} words which can be represented by the digit key mapping.
    They require #{dials.len} digit combinations to represent them.
    #{textonyms.len} digit combinations represent Textonyms.
    END

say "Top 5 in ambiguity:";
say textonyms.sort_by { |_,v| -v.len }.first(5).join("\n");

say "\nTop 5 in length:";
say textonyms.sort_by { |k,_| -k.len }.first(5).join("\n");

Output:

$ sidef textonyms.sf < unixdict.txt 
There are 24978 words which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 in ambiguity:
["729", ["paw", "pax", "pay", "paz", "raw", "ray", "saw", "sax", "say"]]
["269", ["amy", "any", "bmw", "bow", "box", "boy", "cow", "cox", "coy"]]
["2273", ["acre", "bard", "bare", "base", "cape", "card", "care", "case"]]
["726", ["pam", "pan", "ram", "ran", "sam", "san", "sao", "scm"]]
["782", ["pta", "pub", "puc", "pvc", "qua", "rub", "sub"]]

Top 5 in length:
["25287876746242", ["claustrophobia", "claustrophobic"]]
["7244967473642", ["schizophrenia", "schizophrenic"]]
["666628676342", ["onomatopoeia", "onomatopoeic"]]
["49376746242", ["hydrophobia", "hydrophobic"]]
["2668368466", ["contention", "convention"]]

Swift

import Foundation

func textCharacter(_ ch: Character) -> Character? {
    switch (ch) {
    case "a", "b", "c":
        return "2"
    case "d", "e", "f":
        return "3"
    case "g", "h", "i":
        return "4"
    case "j", "k", "l":
        return "5"
    case "m", "n", "o":
        return "6"
    case "p", "q", "r", "s":
        return "7"
    case "t", "u", "v":
        return "8"
    case "w", "x", "y", "z":
        return "9"
    default:
        return nil
    }
}

func textString(_ string: String) -> String? {
    var result = String()
    result.reserveCapacity(string.count)
    for ch in string {
        if let tch = textCharacter(ch) {
            result.append(tch)
        } else {
            return nil
        }
    }
    return result
}

func compareByWordCount(pair1: (key: String, value: [String]),
                        pair2: (key: String, value: [String])) -> Bool {
    if pair1.value.count == pair2.value.count {
        return pair1.key < pair2.key
    }
    return pair1.value.count > pair2.value.count
}

func compareByTextLength(pair1: (key: String, value: [String]),
                         pair2: (key: String, value: [String])) -> Bool {
    if pair1.key.count == pair2.key.count {
        return pair1.key < pair2.key
    }
    return pair1.key.count > pair2.key.count
}

func findTextonyms(_ path: String) throws {
    var dict = Dictionary<String, [String]>()
    let contents = try String(contentsOfFile: path, encoding: String.Encoding.ascii)
    var count = 0
    for line in contents.components(separatedBy: "\n") {
        if line.isEmpty {
            continue
        }
        let word = line.lowercased()
        if let text = textString(word) {
            dict[text, default: []].append(word)
            count += 1
        }
    }
    var textonyms = Array(dict.filter{$0.1.count > 1})
    print("There are \(count) words in '\(path)' which can be represented by the digit key mapping.")
    print("They require \(dict.count) digit combinations to represent them.")
    print("\(textonyms.count) digit combinations represent Textonyms.")

    let top = min(5, textonyms.count)
    print("\nTop \(top) by number of words:")
    textonyms.sort(by: compareByWordCount)
    for (text, words) in textonyms.prefix(top) {
        print("\(text) = \(words.joined(separator: ", "))")
    }

    print("\nTop \(top) by length:")
    textonyms.sort(by: compareByTextLength)
    for (text, words) in textonyms.prefix(top) {
        print("\(text) = \(words.joined(separator: ", "))")
    }
}

do {
    try findTextonyms("unixdict.txt")
} catch {
    print(error.localizedDescription)
}

Output:

There are 24978 words in 'unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 5 by number of words:
269 = amy, any, bmw, bow, box, boy, cow, cox, coy
729 = paw, pax, pay, paz, raw, ray, saw, sax, say
2273 = acre, bard, bare, base, cape, card, care, case
726 = pam, pan, ram, ran, sam, san, sao, scm
426 = gam, gao, ham, han, ian, ibm, ibn

Top 5 by length:
25287876746242 = claustrophobia, claustrophobic
7244967473642 = schizophrenia, schizophrenic
666628676342 = onomatopoeia, onomatopoeic
49376746242 = hydrophobia, hydrophobic
2668368466 = contention, convention

Tcl

set keymap {
    2 -> ABC
    3 -> DEF
    4 -> GHI
    5 -> JKL
    6 -> MNO
    7 -> PQRS
    8 -> TUV
    9 -> WXYZ  
}

set url http://www.puzzlers.org/pub/wordlists/unixdict.txt

set report {
There are %1$s words in %2$s which can be represented by the digit key mapping.
They require %3$s digit combinations to represent them.
%4$s digit combinations represent Textonyms.

A %5$s-letter textonym which has %6$s combinations is %7$s:

  %8$s
}

package require http
proc geturl {url} {
    try {
        set tok [http::geturl $url]
        return [http::data $tok]
    } finally {
        http::cleanup $tok
    }
}

proc main {keymap url} {
    foreach {digit -> letters} $keymap {
        foreach l [split $letters ""] {
            dict set strmap $l $digit
        }
    }
    set doc [geturl $url]
    foreach word [split $doc \n] {
        if {![string is alpha -strict $word]} continue
        dict lappend words [string map $strmap [string toupper $word]] $word
    }

    set ncombos [dict size $words]
    set nwords 0
    set ntextos 0
    set nmax 0
    set dmax ""
    dict for {d ws} $words {
        puts [list $d $ws]
        set n [llength $ws]
        incr nwords $n
        if {$n > 1} {
            incr ntextos $n
        }
        if {$n >= $nmax && [string length $d] > [string length $dmax]} {
            set nmax $n
            set dmax $d
        }
    }
    set maxwords [dict get $words $dmax]
    set lenmax [llength $maxwords]
    format $::report $nwords $url $ncombos $ntextos $lenmax $nmax $dmax $maxwords
}

puts [main $keymap $url]

Output:

There are 24978 words in http://www.puzzlers.org/pub/wordlists/unixdict.txt which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
3548 digit combinations represent Textonyms.

A 6-letter textonym which has 6 combinations is 2253:

  able bake bald bale cake calf

VBScript

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objInFile = objFSO.OpenTextFile(objFSO.GetParentFolderName(WScript.ScriptFullName) &_
	"\unixdict.txt",1)
Set objKeyMap = CreateObject("Scripting.Dictionary")
	With objKeyMap
		.Add "ABC", "2" : .Add "DEF", "3" : .Add "GHI", "4" : .Add "JKL", "5"
		.Add "MNO", "6" : .Add "PQRS", "7" : .Add "TUV", "8" : .Add "WXYZ", "9"
	End With

'Instantiate or Intialize Counters
TotalWords = 0
UniqueCombinations = 0
Set objUniqueWords = CreateObject("Scripting.Dictionary")
Set objMoreThanOneWord = CreateObject("Scripting.Dictionary")

Do Until objInFile.AtEndOfStream
	Word = objInFile.ReadLine
	c = 0
	Num = ""
	If Word <> "" Then
		For i = 1 To Len(Word)
			For Each Key In objKeyMap.Keys
				If InStr(1,Key,Mid(Word,i,1),1) > 0 Then
					Num = Num & objKeyMap.Item(Key)
					c = c + 1
				End If
			Next
		Next
		If c = Len(Word) Then
			TotalWords = TotalWords + 1
			If objUniqueWords.Exists(Num) = False Then
				objUniqueWords.Add Num, ""
				UniqueCombinations = UniqueCombinations + 1
			Else
				If objMoreThanOneWord.Exists(Num) = False Then
					objMoreThanOneWord.Add Num, ""
				End If
			End If
		End If
	End If
Loop	

WScript.Echo "There are " & TotalWords & " words in ""unixdict.txt"" which can be represented by the digit key mapping." & vbCrLf &_
			 "They require " & UniqueCombinations & " digit combinations to represent them." & vbCrLf &_
                         objMoreThanOneWord.Count &  " digit combinations represent Textonyms."

objInFile.Close

Output:

There are 24978 words in "unixdict.txt" which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Wren

Translation of: Kotlin

Library: Wren-str

Library: Wren-sort

Library: Wren-fmt

import "io" for File
import "./str" for Char, Str
import "./sort" for Sort
import "./fmt" for Fmt

var wordList = "unixdict.txt"
var DIGITS = "22233344455566677778889999"
var map = {}
var countValid = 0
var words = File.read(wordList).trimEnd().split("\n")
for (word in words) {
    var valid = true
    var sb = ""
    for (c in Str.lower(word)) {
        if (!Char.isLower(c)) {
            valid = false
            break
        }
        sb = sb + DIGITS[Char.code(c) - 97]
    }
    if (valid) {
        countValid = countValid + 1
        if (map.containsKey(sb)) {
            map[sb].add(word)
        } else {
            map[sb] = [word]
        }
    }
}
var textonyms = map.toList.where { |me| me.value.count > 1 }.toList
var report = "There are %(countValid) words in '%(wordList)' " +
             "which can be represented by the digit key mapping.\n" +
             "They require %(map.count) digit combinations to represent them.\n" +
             "%(textonyms.count) digit combinations represent Textonyms.\n"
System.print(report)

var longest = Sort.merge(textonyms) { |i, j| (j.key.count - i.key.count).sign }
var ambiguous = Sort.merge(longest) { |i, j| (j.value.count - i.value.count).sign }

System.print("Top 8 in ambiguity: \n")
System.print("Count   Textonym  Words")
System.print("======  ========  =====")
var f = "$4d    $-8s  $s"
for (a in ambiguous.take(8)) Fmt.print(f, a.value.count, a.key, a.value)

f = f.replace("8", "14")
System.print("\nTop 6 in length:\n")
System.print("Length  Textonym        Words")
System.print("======  ==============  =====")
for (l in longest.take(6)) Fmt.print(f, l.key.count, l.key, l.value)

Output:

There are 24978 words in 'unixdict.txt' which can be represented by the digit key mapping.
They require 22903 digit combinations to represent them.
1473 digit combinations represent Textonyms.

Top 8 in ambiguity: 

Count   Textonym  Words
======  ========  =====
   9    269       amy any bmw bow box boy cow cox coy
   9    729       paw pax pay paz raw ray saw sax say
   8    2273      acre bard bare base cape card care case
   8    726       pam pan ram ran sam san sao scm
   7    4663      gone good goof home hone hood hoof
   7    7283      pate pave rate rave saud save scud
   7    782       pta pub puc pvc qua rub sub
   7    426       gam gao ham han ian ibm ibn

Top 6 in length:

Length  Textonym        Words
======  ==============  =====
  14    25287876746242  claustrophobia claustrophobic
  13    7244967473642   schizophrenia schizophrenic
  12    666628676342    onomatopoeia onomatopoeic
  11    49376746242     hydrophobia hydrophobic
  10    2668368466      contention convention
  10    6388537663      mettlesome nettlesome

zkl

Translation of: Python

Like the Python example, this solution uses the Unix Dictionary, rather than the textonyms word list as I don't want to parse the HTML.

URL:="http://www.puzzlers.org/pub/wordlists/unixdict.txt";
var ZC=Import("zklCurl");
var keypad=Dictionary(
   "a",2,"b",2,"c",2,  "d",3,"e",3,"f",3,  "g",4,"h",4,"i",4,
   "j",5,"k",5,"l",5,  "m",6,"n",6,"o",6,  "p",7,"q",7,"r",7,"s",7,
   "t",8,"u",8,"v",8,  "w",9,"x",9,"y",9,"z",9);
//fcn numerate(word){ word.toLower().apply(keypad.find.fp1("")) }
fcn numerate(word){ word.toLower().apply(keypad.get) } //-->textonym or error
println("criticisms --> ",numerate("criticisms"));

words:=ZC().get(URL); //--> T(Data,bytes of header, bytes of trailer)
words=words[0].del(0,words[1]);  // remove HTTP header
println("Read %d words from %s".fmt(words.len(1),URL));

wcnt:=Dictionary();
foreach word in (words.walker(11)){  // iterate over stripped lines
   w2n:=try{ numerate(word) }catch(NotFoundError){ continue }; 
   wcnt.appendV(w2n,word);  // -->[textonym:list of words]
}

moreThan1Word:=wcnt.reduce(fcn(s,[(k,v)]){ s+=(v.len()>1) },0);
maxWordPerNum:=(0).max(wcnt.values.apply("len"));

("There are %d words which can be represented by the Textonyms mapping.\n"
"There are %d overlaps.").fmt(wcnt.len(),moreThan1Word).println();
 
println("Max collisions: %d words:".fmt(maxWordPerNum));
foreach k,v in (wcnt.filter('wrap([(k,v)]){ v.len()==maxWordPerNum })){
   println("  %s is the textonym of: %s".fmt(k,v.concat(", ")));
}

Output:

criticisms --> 2748424767
Read 25104 words from http://www.puzzlers.org/pub/wordlists/unixdict.txt
There are 22903 words which can be represented by the Textonyms mapping.
There are 1473 overlaps.
Max collisions: 9 words:
  729 is the textonym of: paw, pax, pay, paz, raw, ray, saw, sax, say
  269 is the textonym of: amy, any, bmw, bow, box, boy, cow, cox, coy