Subtitles are text added to a film or television program. They usually appear at the bottom of the screen, though they may occur at the top when placement at the bottom would make them illegible or they would obstruct an important element on screen.
Frequently, their purpose is to translate the dialogue and text of a foreign production. It is an alternative to dubbing. When the language of the subtitles is the same as the production's, they serve the purpose of aiding the hearing-impaired. In this case, subtitles are more commonly known as closed captioning.