Some captions are open and can't be turned off. Sign language is still used to a certain extent in television broadcasting, particularly in the United Kingdom. Access for those who don't understand your language Subtitling , not the same as captioning. Despite their seeming similarity, captioning and subtitling have very little in common. The assumed audience for subtitling is hearing people who do not understand the language of dialogue.
Captions notate sound effects and other dramatically significant audio.
Subtitles assume you can hear the phone ringing, the footsteps outside the door, or a thunderclap. Subtitles are always open. Captions are in the same language as the audio. Subtitles are a translation. Subtitles also translate onscreen type in another language, e.g., a sign tacked to a door, a computer monitor display, a newspaper headline, or opening credits.