So I shared the video with a friend yesterday. To my surprise they were not convinced. Which makes me wonder if it breaks down for very adept lip readers.
It doesn’t pick quite the right movement for some of the subtler sounds. I’m still trying to quantify where it breaks down for me.
For me, I think it's that the movement of the rest of the mouth and the muscles/skin in the face (and the light/shadow as a result) doesn't match up with what I expect. It looks like the facial animation from a good videogame cutscene
It seems almost off from the audio. I know it isn’t but it just feels that way. Also the lack of eye movement and a few other “natural” things throw it off a bit for me.