> Last time I looked into TTS systems for German, Google was the only game in town. What I wouldn't give for a viable alternative! It doesn't even need to be open source, I'd be quite ready to pay top dollar.

Will you still pay top dollar if it is open source though? :D

Piper TTS[0] (MIT Licensed; developed by main dev of Larynx TTS, Mimic3 TTS & Rhasspy voice assistant) has support for ~30 languages, at least some of which have multiple voices available--in a range of quality & data licenses.

And, particularly fortuitous for your needs, potentially, there's at at least one German voice that was recorded[1] specifically for Piper[2] (with emotion variants and CC0-licensed, no less :) )...

Check out `thorsten` & `thorsten_emotional` on the samples page: https://rhasspy.github.io/piper-samples/

I can't speak to the quality of the German voice specifically but for English at least I've found Piper's quality & range of voices of use[3].

---- footnotes ----

[0] https://github.com/rhasspy/piper

[1] https://www.youtube.com/playlist?list=PL19C7uchWZeojjI5FUk3q...

[2] In addition to other German voices based on other sources: https://huggingface.co/rhasspy/piper-voices/tree/main/de/de_...

[3] Somewhat of an understatement.