There's no way to switch back to the original audio track? I agree you shouldn't have to but I'm wondering if it's possible.
Not if you Airplay to your TV. I get random foreign languages when I watch English speaking YouTubers. No way to enable subtitles or change the language. It's a known bug according to the internet.
You can change the audio track back to the original.
Not sure if it remembers your preference, though, so if it doesn't that probably grates.