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letterize_ - phone-number to letter-mnemonic generator


letterize nnnnnnn


This program tries to help you find a letter mnemonic matching a given phone number.

It emits to standard output each possible pronounceable mnemonic, one per line, using the American standard mapping of dial letters to numbers (2 goes to ABC, 3 to DEF, 4 to GHI, 5 to JKL, 6 to MNO, 7 to PRS, 8 to TUV, 9 to XYZ).

The program uses a table of pronounceable letter-triples derived from a dictionary scan. Each potential mnemonic must be such that all of its letter-triples are in the table to be emitted. About 30% of possible triples are considered pronounceable.

A typical 7-digit phone number has 19,683 possible mnemonics, but this test usually cuts the list down to a few hundred or so, a reasonable number to eyeball-check. For some numbers, the list will, sadly, be empty.

It's best to leave out punctuation such as dashes and parens.


The filtering method doesn't know what plausible medial triples are not reasonable at the beginnings and ends of words.

I'm not sure what table position 0 (which is what 0 and 1 are mapped to) means. If you figure it out, you tell me. I really should have generated my own table, but that would have been more work than this seemed worth -- if your number contains either, you probably need to generate your mnemonic in disjoint pieces around the digits anyway.


Eric S. Raymond <>. It's based on a table of plausible letter-triples that had no name attached to it. Surf to for updates and related resources.

09/06/2021 letterize