Description: TTS using `window.SpeechSynthesisUtterance` and STT using
`window.SpeechRecognition`.
Learn: I tried to implment download as mp3/wav and searched on google, stackoverflow and claude
but nothing worked (no working solutions).
My favorite speakers:
FEMALE: 191 (treble), 192 (warm) MALE: 193 (warm) [TODO: Try Rishi (en-IN) with rate 1.5 and pitch 1.2], test in this playground