Wraps someone's words, a name, or an order and hands it on to the listener. After a noun it means "is called" or "my name is", which is how the speaker introduces himself in one example; after a command it reports an instruction ("who told you to ask?", "they set it up for us to practice"). The related 다고 하다 and ㄴ다고 하다 do the same job for reported statements, while 라고 하다 handles nouns and commands. In captions it often shows up clipped, and the exclamation form expresses surprise at what was just said.
Register: neutral; very frequent in speech and captions