rtfd/readthedocs.org — pull request #1018 by dpgeorge (2014-11-07 20:44:19+00:00)
Title: Add support for many languages in lang_slug URL.

Add support for 142 languages using ISO 639-1 2-letter codes. If the selected language is not available in Sphinx then Sphinx simply prints "not available for built-in messages" and uses English.