I know that if you have a “forced” subtitle SubRip Text (.srt), that subtitle will always start start with that specific media. It doesn’t matter whether the actors are talking in foreign, alien or local language, as long as there’s text within the subtitle, it will display it.
Plex has an option to display subtitle when a foreign audio is chosen (depending on your chosen language for plex). But that’s a different story.
But if you’re saying that closed caption is on again (excluding the forced subtitle tracks you were refering to) even though its off on TV. Then I’m positively sure its from your cable box, digital receiver, satellite box or something connected via HDMI that is sending you those closed captions.
If you have something that’s hooked on (and I believe its your DVR/cable box) then use its remote, goto its settings and turn it off.
A quick search on the internet and I think I found your answer HERE. It may be old, but hope that helps you.
EDIT: Just wanted to add another site HERE from yahoo answers on how to turn CC off.
