Nobody here was talking about subtitles.

Then about what?

I assumed that was meant with "dubbing".

https://en.wikipedia.org/wiki/Dubbing

Oh, then I guess I did not wanted to understand. Does youtube really just changes the audiotrack of videos? I never encountered that so far.

Yep, with a robotic sounding voice. They decided I don't speak english so I either download the video externally or I must every single time select english as audio track.