The document discusses speech act theory, which proposes that language is used not just to inform or describe, but also to perform actions. There are three types of speech acts: locutionary acts (the literal meaning of an utterance), illocutionary acts (the intended meaning), and perlocutionary acts (the effect on the listener). Searle identified five categories of illocutionary acts. Indirect speech acts occur when the structure of an utterance does not directly match its intended function, like using a declarative to make a request. Felicity conditions specify when it is appropriate to interpret an utterance as a particular speech act.