Yes, it is possible, you can set a request right here like helping us with some files. You can help us with this.
Upload somewhere .bik cutscenes with Deutsch language.
It is located somewhere in Languages folder, it also can be in FCData. There are xml files and .bik - all those are collect the language itself.
If you could present for us those files, we'll try to implement this language into the game.
We also plan to add soon the GUIDE how any user can create translation on any language.
Wenn Sie Probleme haben, diese Dateien zu finden und bearbeitung, dann überlassen Sie das ruhig uns. Wir hatten ohnehin vor, Deutsch als dritte Hauptsprache hinzuzufügen.
Viel Glück!
Here should be the Files for German: https://www.dropbox.com/t/eoJdTKrLhfuZHlAG
hope it helps plus it should work with the Steam version too but i cant tell because i dont know how to code ;_;