Subtitles are captions of text that appear on screen during films or television programs usually either to enable deaf or hard of hearing people to watch and understand what is happening or to translate dialogue spoken in another language or with a heavy accent. Subtitles are often prepared beforehand to the viewing, as is the case in cinemas or with DVDs and other recorded films, however live subtitles are also frequently used to cover live television such as news broadcasts. Live subtitles are provided by special trained individual who are skilled at typing quickly on highly specialised keyboards.

Subtitles are also frequently used to translate film or television into another language and it is often preferred to dubbing, many foreign language films available on DVD will include the option for a dubbing track or subtitles, many people will opt for subtitles as dubbing can often poorly performed and can look and sound ridiculous. It is a frequent practice for English language films and television to be exported to other languages where it will be broadcast will subtitles for a non English speaking audience.

Specialised subtitles for deaf and hard of hearing people also exist which will included captions containing information other than spoken dialogue, for example a sigh, or laughter many be explained in the subtitles so the hard of hearing person can understand the tone or speech and mood of characters. Subtitles may also be used to convey other important sounds that occur such as explosions or a gunshot for example.