In the philosophy of language and linguistics, a speech act is an utterance considered as an instance of action in a social context rather than as the mere expression of a proposition. To say "I resign", "I apologise" or "You're fired" is, in suitable circumstances, to perform the very act of resigning, apologising or dismissing, not simply to describe it. Speech-act theory therefore treats speaking a language as a kind of rule-governed social behaviour in which people make claims, issue orders, ask questions, make promises and so on by means of utterances.
Following J. L. Austin and John R. Searle, many accounts distinguish at least three levels of act in ordinary utterances: the locutionary act of producing a meaningful expression, the illocutionary act performed in saying something (such as asserting, warning, requesting or promising), and the perlocutionary act consisting in its further effects on an audience, such as persuading, amusing or alarming them. Later work has added notions such as metalocutionary acts, which organise or comment on the discourse itself, and has analysed performative utterances and indirect speech acts, in which one kind of act is performed by way of another.
