Comment 2 for bug 823741

Even if the problem is still present in gnome-control-center, supposedly affecting GNOME users, it no longer shows up in Ubuntu. This is due to recently uploaded changes to the Ubuntu specific patches in accountsservice.
https://launchpad.net/ubuntu/+source/accountsservice/0.6.15-2ubuntu3

Now, when you in Ubuntu query accountsservice for the Language, and the Language property has not yet been set, accountsservice returns a sensible fallback value (typically the system language) instead of the empty string. For that reason the questionable cc_common_language_get_current_language() function is never called.