Test/Standardize TTS Voice Rates

[ragar3]

Currently the TTS voice options vary based on the user's OS, meaning the speech rate depends on the OS. Google voices specifically are unintelligible even at rate = 2 (tested on Google Chrome on Windows). Voices from different providers should be tested and if possible, code should be added to make sure speech is understandable on all platforms. If there is some way to standardize each speech rate based on words per minute, that would likely be ideal.

From issue #1: "It's possible using something like Howler.js would fix some of these platform-specific quirks, at least with respect to audio."

[steinbro]

That's a good catch. It's quite possible the rate that we set in the app is a multiple of the user's system default rate, so perhaps we should default to 1x and let the user adjust from there. Alternatively, if there's a way to query the system rate, we could do some normalization based on that value.

Regarding Howler.js, I'm not aware of any TTS-related functionality, so not sure it would be relevant here.

[sebastianovide]

2 is fast also in Chrome and firefox under linux, windows and android... should we do 2 only for Apple and 1 for the rest ?

[steinbro]

I think we need more precise control, maybe tenths. 2 may be too fast for a default, but 1 is somewhat slow.