I would like to join the translation effort over on Weblate but it seems I have to ask someone to add croatian. Not sure how it works, or if I can add it myself, so asking here!
I don’t know if you can add the language yourself but I added it: Mobilizon - Croate @ Weblate 
If you’re interested ou can also translate the websites https://joinmobilizon.org and https://mobilizon.org on JoinMobilizon - Croate @ Weblate and mobilizon.org - Croate @ Weblate.
Thank you very much 
Registered users can indeed add new languages themselves.
No, thank you! Appreciate it a ton. Can’t wait to get to work on it.
I could have missed it? Didn’t find the option to do so, but oh well! It’s added now and I’m happy