Handling for missing language codes is needed.
http://wikidata-test-repo.wikimedia.de/wiki/Data:Q24788 shows some entries w/o language names/codes.
Version: master
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=37542
https://bugzilla.wikimedia.org/show_bug.cgi?id=42396