23.10 is considerably slower with some built in TTS voices under Windows 10. In this example, both {{tts en_GB}} and {{tts en_US:}} are correctly installed on my system:
However, for some reason, when using any template that uses the US version, an annoyng “Precessing” windopws appears for 1-4 seconds after reviewing any card:
2.1.66 worked fine with GB and US TTS.
Nothing really serious once you find out what’s the problem, which took me a while.