Searle refined Austin's speech-act theory into five mutually exclusive classes of illocutionary act, distinguished by what the speaker is doing with an utterance: assertives commit the speaker to the truth of a proposition, directives try to get the hearer to do something, commissives commit the speaker to a future action, expressives convey a psychological state, and declarations change the world by the saying itself.
This taxonomy is a foundational scheme for pragmatic and discourse annotation: it labels the function of an utterance rather than its topic. Tag each codeable utterance with the single class that best captures its primary illocutionary force. When an utterance blends functions, code the dominant act and note the secondary force in the rationale.