Re: are there hot keys for raising and lowering speed of speech?
You missed 'em. And you can bring up the list of same when NVDA is running with NVDA+N,H,Q, which opens up the Commands Quick Reference.
Open that and search for the section entitled,
Synth settings ring
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Science has become just another voice in the room; it has lost its platform. Now, you simply declare your own truth.
~ Dr. Paul A. Offit, in New York Times article, How Anti-Vaccine Sentiment Took Hold in the United States, September 23, 2019