System.Speech.Synthesis.SpeechSynthesizer can't be configured properly for third party text readers (e.g., Koharu Rokka, https://www.ah-soft.com/cevio/rikka/).
Using SAPI, I was able to set it up well with a third party text reader.
So I rewrote it to use SAPI.
This PR depends on https://github.com/Marak/say.js/pull/121
System.Speech.Synthesis.SpeechSynthesizer can't be configured properly for third party text readers (e.g., Koharu Rokka, https://www.ah-soft.com/cevio/rikka/). Using SAPI, I was able to set it up well with a third party text reader. So I rewrote it to use SAPI.