I tried with text to speech OFFLINE (instead of Azure).
The same problem. No difference.
I did not have a freeze of the ATC in my test, but often the ATC voice was just silent and only “my” (pilot) voice was there.
Same problem happens in Azure as well.
Often suddenly no sound of the ATC voice, sometimes complete ATC freeze, often a mix of English and German words spoken.
All these problems startet with World Update 4. Super annoying.
(I’m on Windows 10 in German, Language of FlightSim also in German “DE-DE”)
Like I said: It worked until World Update 4… since then, ATC is a total mess.