Greasy Fork

It works fine .. but it's pretty annoying that you can't disable the subtitles.
Probably only useful for deaf people.

There is a bug in the code, so it continues trying to set the language forever. Once I fix the error, it should only try to change the language a number of times after you accessed or changed the page (i.e. clicked on a different video).

After fixing the bug, you should be able to disable the subtitles without them being re-enabled by this script.

Edit: Due to the lack of time, fixing the bug will take a few more days, but by next week, or worst case scenario in a week, the bug should be fixed.