Hi, I am using the development version of C:DDA. I noticed it defaults to English again, but my system language is German. In 0.9, C:DDA was German by default, now it’t back to English.
So how do I select the language for C:DDA in the development version?
Can nobody help me? 
No clue personally. I’d suggest asking down on the translation boards at the bottom of the forum, they can probably get you pointed in the right direction there. 
No clue, but made an issue: https://github.com/CleverRaven/Cataclysm-DDA/issues/6357
Sorry for the delay, I finally had some time to dig into this, and it’s a good thing I had time, because it took all evening. I think what happened is some bad .po files got checked in, which has been keeping the gettext tools from working properly. I imported the latest batch of .po files from launchpad, so based on those a:
make LANGUAGES
or
make LANGUAGES=de_DEShould create fresh .mo files, which cataclysm should then start using.
There was also an issue with some code that tried to use language specific names for game worlds that was causing a crash, but sounds like you didn’t hit that one.
Okay, with your help (also in GitHub) I managed to get my localized version working again.
Thanks.