I believe i have found a problem. I can't find a ticket on it so i don't know if it has been reported.
Lets say you create a new language file in admin, copy from english so you can start transulating it.
Now, if you install a module that was not previously installed when that language file was created, the module install only puts language keys in the default en language file, thus you end up with this showing up if your site is running the other language file.
Shouldn't the module install put a default english version of the language key into all the installed languages?
After module reinstallation all language keys for the module will be recreated, so save this changes you need to translate module language file which is in module install directory!
So. i guess this also means module developers such as myself will have to create language files for all languages, or force the people buying the mods to manually enter language keys for their installed languages.
Screw it. Guess i will have to rewrite my modules to do that instead. Because leaving them empty looks like crap.