Currently, one of the more important steps in making a language generally usable in Linux distros is to establish a glibc locale entry for it with the upstream.
Locales are a combination of language specific information (sorting order, number formatting, etc.) and country-specific information (currency, address format, telephone number format, etc.) that allows GNOME to better understand how to present information in that language / country combination.
For a quick check to see if a locale exists for your language / country, try this link:
Tools for glibc locale development and testing
The GNOME internationalization leader is willing to help people develop these somewhat technical locale files and is the author of the 2xlibre tool. If you intend to attempt development of a locale for your language, it is recommended that you join the GNOME Internationalization mailing list and discuss it there first.