German Language

I wrote some month ago about the language problems I have. The problem is, that the German Language file I created is not loaded. WordPress has different kinds of the German Language integrated. I use the general German. You said me, I should use the Formal one, to get the file loaded. That worked for some time. But actually my file is not loaded anymore. So could you please take a look about how you have integrated the WordPress Language loader, so that my general German Translation (“Du Form”, not ‘Formal’ “Sie Form”) get loaded? Thank you!