I think Jean-Philippe and Richard both wanted to have bit more granular control of the speech rate. Jean-Philippe proposed using a slider.
I originally had a slider, but I discovered that slider accessibility is poor, at least in older Android Talkback that I have.
Instead, I could add a 6th choice, custom, where you could enter a decimal value between 1-10, let's say 3.5 for instance. How does that sound?
It only affects the self-voicing speed, VoiceOver/Talkback speech rate I cannot change.
Best regards,
Harri