Closed captions are a text version of the spoken part of a television, movie, or computer presentation. ... For example, captions can be read when audio can't be heard, either because of a noisy environment, such as an airport, or because of an environment that must be kept quiet, such as a hospital.

What do you put on closed captions?

FCC Caption Quality Standards

With accuracy, the FCC states that closed captions must match the spoken words in the audio to the fullest extent. This includes preserving any slang or accents in the content and adding the non-speech elements. For live captioning, some leniency does apply.

Should I use closed captions or subtitles?

While video subtitles are intended for viewers who can't understand the language being spoken, captions are intended for viewers who can't hear the audio. Captions (which can refer to closed captions or open captions) include the dialogue as well as any other relevant audio.