YtShadow

Shadowing is a deceptively simple, little-known language learning technique. You take a native audio recording, with a transcript and you speak along at as close to the same time as you can. That’s it.
https://howtogetfluent.com/shadowing-for-language-learning/

This addon makes youtube.com as shadowing platform using video and subtitle.
Listen one sentence and type it, and optionally you could speak it loud.

https://github.com/cashewnuts/yt-shadow