The youtube video is subtitled, how can I turn it on on my Apple TV?
I tried configuring languages and closed caption, but didn't work.
The Apple TV doesn't support YouTube closed captioning. The closed captioning you've enabled is where video files have subtitles. The same functionality was missing on the pre-iOS 6 YouTube app, so I'm not surprised that it doesn't exist on the Apple TV.
If you want to submit feedback to Apple about this, you can do so here.