Congratulations for your German Mycroft !. Please, consider to share your experience, editing current wiki or creating a new one, as you prefer.
About replace remote STT by local German one, my design decision has been start a new client, lclient.
Modify current one had some problems: Mycroft team is busy to accept big pull requests, probably due to stability and regression test efforts; local STT seems not in his business plan; … . I don’t like forks, it is expected a rejoin when “lclient” was fully stable and Mycroft team has time for this improvement.
I see you have a very good level on computer science, you should no have big problems trying with this client.
Note: in last months I’ve working more in the hardware aspects than in the software. I’ve not updated with latest Mycroft versions, thus, some issue could appear.
(Why hardware now: I do not imagine Mycroft as an object to buy and place in a room, but as a hidden, embedded AI present in the house. Thus, I’m working in distributed microphones/speakers, integration with Z-wave and zigbee devices, … ).