in reply to Text::Levenshtein question
I had a fine answer for you - translate to utf8 and Text::Levenshtein ought to work. Unfortunately, a quick grep for "ASSAM" over /usr/lib/perl5/5.8.4/unicore/*.txt turns up nothing. Encode::Supported also admits to weakness in Indic languages, with no mention of ISCII.
There are influential linguists in the perl crowd. Perhaps support could be added, but you'd probably need to help with the effort.