For more information including compatibility, examples and test cases, see

0.1. Soundex: (import (slib soundex))

This implementation of the Russell Soundex algorithm is based on Knuth, Vol. 3 "Sorting and searching", pp.391-2: note, reexported by (robin text)

The soundex algorithm returns a code for a word, and equivalent sounding words should return equivalent codes:

> (soundex "pair")
> (soundex "pare")
> (soundex "rabbit")
> (soundex "racket")
> (soundex "smith")
> (soundex "smythe")