As someone who speaks German, it feels puzzling to me why I would teach my dog German commands (even though I have a GSD), these are just the regular words/phrases for things but in a different language.
1] regionally unfamiliar language, dog will obey your commands, but not commands of regional language.
2] parrallel handling, different dogs trained in different languages dont step on each others task,in response to the same cue command.
e.g. left dog, sprech im ze deutsch - right dog, govorite po russki
i get them mixed up when cold, but if speaking for a while i can get in a zone.
my spelling is atrocious i think i see where you complain:
Sprechen Sie Deutsch %:P