Hi there,
For the case you want to build lucene index for Mongolian, just add one line in /org/apache/lucene/analysis/standard/StandardTokenizer.jj, find "#LETTER:", add:
"\ue235"-"\ue293",
rebuild your lucene 1.4, and then you can search Mongolian Unicode letters.
Regards,
Shi Yusen/Beijing Langhua Ltd.