Is your feature request related to a problem? Please describe.

Some users think that some of the SAPI5 voices are not fast enough even at the highest rate.

Synthesizers such as OneCore supports rate boosting and maximum 6x speed. But SAPI5 voices usually only support maximum 3x speed.

Describe the solution you'd like

Add rate boost support for SAPI5 voices as well.

eSpeak NG and OneCore voices support higher rate natively, but SAPI5 voices don't, so an audio processing library is needed to speed up the audio.

We can use the sonic library, which is also being used by eSpeak NG.

As now the audio is being handled by NVDA itself, this becomes possible.

Describe alternatives you've considered

Additional context