[XeTeX] Testing custom hyphenation patterns

[Aleksandr Andreev]

Hello folks,

I'm working on some hyphenation patterns for Church Slavonic. I'm not
using PatGen2 - given the agglutinative nature of the language, I
think this would be too tedious. Rather, I'm writing down patterns by
hand.

I would like to test my patterns in XeTeX using the \showhyphens
syntax to see how I'm doing.

Question: how do I load the patterns? As I understand from the
documentation, patterns are read only by IniTeX. I've read on the 'net
that I need to modify language.dat. Where is this file and what do I
need to do with it? I'd rather not break my TeX installation.

Thanks,

Aleksandr.