Subtitling (a.k.a. spotting, timing, cueing, origination)
If this were a wedding toast, we would write: “Oxford English Dictionaries defines subtitles as “Captions displayed at the bottom of a cinema or television screen that translate or transcribe the dialogue or narrative”. But it’s not a wedding and Oxford University Press doesn’t know as much about subtitles as we do.
Very simply put, “subtitles are a version of a film or television program’s dialog that appears onscreen” (Wikipedia). But they are actually so much more than that!
Subtitles can be created in the same language of the audio or in a different one, and each has specific uses.