Alexandre Schmidton Stack Overflow • Recommends
On “Force YouTube closed captions via URL”
As per link to this video the parameters can only be forced for embedded videos. So you'd have to use this:
link to this video
... instead of:
link to this video
I also faced an issue that videos would not show captions even using the parameters above and I solved this with the solution proposed on link to this video, which states you have to enter YouTube studio, edit the video, go to the "Subtitles" section and click the "Duplicate and Edit" option i.e. the video must have a manually defined subtitle for these parameters to work as expected. This means there's no way you can force auto-translated our auto-generated subtitles to show.
Bonus: when using the /embed/ form, videos do not start playing automatically. You can do…