PHP Functions Essential Reference

soundex

string soundex(string string) 

Calculate a string’s soundex key

Returns:

String containing a soundex key; FALSE on error

Description:

soundex() calculates the soundex key for a string. Soundex keys are short alphanumeric representations of a word’s English pronunciation.

Version:

PHP 3+, PHP 4+

See also:

To analyze the similarity of two strings:

levenshtein() 
similar_text() 

Another method for generating phonetic-based keys:

metaphone() 

Full description of the soundex algorithm:

The Art of Computer Programming, Volume 3 (Donald Knuth)

Example:

Steal the example from metaphone() for comparison

<?php $words = array ('shoos', 'shoes', 'chute', 'schuss'); foreach ($words as $word_one) { $key_one = soundex ($word_one); echo "\n'$word_one' ...