<p>I'm using <a href="http://www.ddj.com/cpp/184401251?pgno=2" rel="nofollow noreferrer">Lawrence Philips Double-Metaphone</a> algorithm with great success, but I have found the odd "unexpected result" for some combinations.</p>

<p>Does anyone else have additions or changes to the algorithm for other parts of it they wouldn't mind sharing, or just the combinations that they've found that do not work as expected.</p>

<p>eg. I had issues between:</p>

<ul>
<li>Peashill and Bushley. (both match with PXL)</li>
<li>Rockliffe and Rockcliffe (RKLF and RKKL)</li>
</ul>

All Soundex, Metaphone and variant schemes are occasionally going to give results that aren't identical to what you expect.  This is unavoidable - they can be regarded as more or less simple hash algorithms with special information preserving properties, and will sometimes produce collisions when you'd rather they didn't, and will sometimes produce differences when you'd rather they didn't.
One possible way of improving things is using 'synonym rings'.  This basically produces lists of words that should be regarded as synonyms, independent of the spelling.  I encountered them in the context of name matching.  For example, variants on Chaudri
included:
CHAUDARY
CHAUDERI
CHAUDERY
CHAUDHARY
CHAUDHERI
CHAUDHERY
CHAUDHRI
CHAUDHRY
CHAUDHURI
CHAUDHURY
CHAUDHY
CHAUDREY
CHAUDRI
CHAUDRY
CHAUDURI
CHAWDHARY
CHAWDHRY
CHAWDHURY
CHDRY
CHODARY
CHODHARI
CHODHOURY
CHODHRY
CHODREY
CHODRY
CHODURY
CHOUDARI
CHOUDARY
CHOUDERY
CHOUDHARI
CHOUDHARY
CHOUDHERY
CHOUDHOURY
CHOUDHRI
CHOUDHRY
CHOUDHURI
CHOUDHURY
CHOUDREY
CHOUDRI
CHOUDRY
CHOUDURY
CHOUWDHRY
CHOWDARI
CHOWDARY
CHOWDHARY
CHOWDHERY
CHOWDHRI
CHOWDHRY
CHOWDHURI
CHOWDHURRYY
CHOWDHURY
CHOWDORY
CHOWDRAY
CHOWDREY
CHOWDRI
CHOWDRURY
CHOWDRY
CHOWDURI
CHOWDURY
CHUDARY
CHUDHRY
CHUDORY
COWDHURY