Description:

Soundex is a phonetic algorithm for indexing names by sound, as pronounced
in English. The goal is for names with the same pronunciation to be encoded
to the same representation so that they can be matched despite minor
differences in spelling. Soundex is the most widely known of all phonetic
algorithms and is often used (incorrectly) as a synonym for "phonetic algorithm".
Improvements to Soundex are the basis for many modern phonetic algorithms.
(Wikipedia, 2007)
This module implements the original soundex algorithm developed by Robert Russell
and Margaret Odell, patented in 1918 and 1922, as well as a variation called
"American Soundex" used for US census data, and current maintained by the
National Archives and Records Administration (NARA).
The soundex algorithm may be recognized from Donald Knuth's The Art of Computer
Programming. The algorithm described by Knuth is the NARA algorithm.
The value returned for strings which have no soundex encoding is defined using
$Text::Soundex::nocode. The default value is undef, however values such as
'Z000' are commonly used alternatives.
For backward compatibility with older versions of this module the $Text::Soundex::nocode
is exported into the caller's namespace as $soundex_nocode.