How do I turn on Closed Captioning on my iPhone or iPod touch?
iOS includes support for playing back open and closed captioning in content such as movies, videos, and podcasts, using the Videos app on the iPhone and iPod touch.
Closed captions appear in a high-contrast white sans serif font against a black background, similar to line 21-style television captions.
You can buy and rent captioned movies from the iTunes Store.
You can find captioned podcasts in iTunes U.
To turn on the Closed Captions, from the Home screen click Settings.
Scroll down to Video.
You will see the following screen.
Turn on Closed Captioning.
Videos with closed captions will now show those captions when played in the Videos app.