Variable: locale-language-names

Alist of locale regexps vs the corresponding languages and coding systems.
Each element has this form:
The first element whose LOCALE-REGEXP matches the start of a
downcased locale specifies the LANG-ENV (language environment)
and CODING-SYSTEM corresponding to that locale. If there is no
appropriate language environment, the element may have this form:
In this case, LANG-ENV is one of generic language environments for an
specific encoding such as "Latin-1" and "UTF-8".