As promised, here's my report on investigating Soundex and related algorithms.
(1) MVEL2 has an utility returning a "key" String from a "word" String that is close to what the Original Soundex algorithm is supposed to return. Not being exactly the same doesn't matter much as long you compare results from the same algorithm.
(2) The National Archives and Records Administration has issued a modified Soundex algorithm, which is supposedly slightly better.
(3) Then, there is the New York State Identification and Intelligence System (NYSIIS) Phonetic Encoder, which is reported to be 2.7% better than Soundex.
(4) A modified version of NYSIIS has also been defined, for both of them see http://www.dropby.com/NYSIIS.html. (I have some doubts whether this page reflects a correct implementation of the original NYSIIS algorithm; e.g., "Bahr" returns "B", which can't be correct.)
All of the above are only useful for English pronounciations of proper names.
(5) For German, there is something called "Kölner Phonetik".
I have implemented (1), (2), (3) and (5) in a class SoundsLikeEvaluatorDefinition implements EvaluatorDefinition, implementing the operator soundsLike (note the capital 'L') in the variants soundsLike or soundsLike[orig] for (1), soundsLike[us] for (2), soundsLike[ny] for (3) and soundsLike[de] for (5).
All of this has been an interesting (for me) exercise, but I really don't know whether any of this should go into Drools. (There is the issue of fixing a NPE with the current implementation that calls the MVEL2 code, though.)
It's up to you, Team, to vote on this; I can contribute the aforementioned class, with "soundsLike" replaced by "soundslike" as a replacement for the current implementation (not requiring the MVEL2 utility) with the option of using the various operator parameters.
Cheers
Wolfgang