There is no fallback (we don't have support for cr, alg or aql).
There is a project in Incubator.
2016-06-09: language is active on translatewiki.net, translators can start to work. We'll process further this task only when a some substantial translation amount is ready per https://translatewiki.net/wiki/Translatewiki.net_languages.
2017-03-26: atj.json exported by Raymond, more translations needed: https://translatewiki.net/wiki/Thread:User_talk:Jeannette_Coocoo/Thanks_for_atj