For setting locale in Ubuntu, what does the
LANGUAGE environment variable mean?
More details are here: Ubuntu Wiki - Environment Variables
For Language, Not all programs have translations for all languages. By default, an English message is shown in place of a nonexistent translation. If you understand other languages, you can set up a priority list of languages. This is done through a different environment variable, called
More details can be found here: GNU gettext manual - The LANGUAGE variable