At first glance, captions and subtitles look almost identical, but just because both are essentially words on the bottom of the screen, does not mean they are interchangeable. They fulfil very different purposes.

Let’s start with captions. Captions are essentially the text version of the sound heard in a tv programme, movie, or video. They are in the language of the medium and so function as an alternative to what is heard.  Captions can either be open or closed. Closed captions can be selected or deselected – in other words, you have a choice to display them or not, whereas open captions are embedded in the video itself and cannot be turned off or removed.

Captions were developed for people with hearing difficulties and so also describe any other sounds that a hearing person will hear, for instance [birds chirp], [phone rings] or [the sound of a train approaching]. Of course, these days, we may want to turn on captions if we are in a noisy or sound-sensitive environment and need to read the dialogue rather than have the sound turned up. Many instructional Youtube videos nowadays have open captions included on the screen to allow the hearing impaired to enjoy them too – or to help facilitate easier understanding where, for instance, the speaker is talking English in a heavy foreign accent.

Subtitles on the other hand are used when it is assumed that the audience can hear the audio, but needs the dialogue provided in text form as well. The most common use for subtitles would be to translate for instance a foreign language film into English for an English-speaking audience. The original audio is intact and audible, but viewers who don’t speak the language can read the English subtitles to understand the dialogue, and still hear the original soundtrack as it was intended.

Sometimes, a movie might offer both captions and subtitles. Let’s say it’s an Afrikaans movie – the captions would be in Afrikaans and would describe all the sounds, e.g. [dramatic music], as well as the dialogue, word for word as it is said by the actors. An Afrikaans, hearing impaired person would select captions to enjoy the movie. An English speaking person would select the English subtitles so that the text at the bottom of the screen is the English translation of what the actors say.

For the people behind the scenes, subtitling is a little more complicated, as the dialogue would need to be professionally translated to the target language, while the captions are based simply on transcription rather than translation.