言语行为理论（speech act theory）是由英国哲学家约翰·奥斯丁(Austin, J.L.)于1962年提出。这个理论认为，我们日常的对话可以分为六种话语区类型：

利用这种分类，有利于学习，而这种好处并不单单局限于第二语言的学习。

香港作家毕华流先生曾就这个理论，在他的作品《顽皮教室》里用“下课了”这三个字来“说明”：在不同的场合下，同一句句子可以有不同的意思，并符合上述的六种话语分类。

A speech act in linguistics and the philosophy of language is an utterance that has performative function in language and communication. According to Kent Bach, "almost any speech act is really the performance of several acts at once, distinguished by different aspects of the speaker's intention: there is the act of saying something, what one does in saying it, such as requesting or promising, and how one is trying to affect one's audience." The contemporary use of the term goes back to J. L. Austin's development of performative utterances and his theory of locutionary, illocutionary, and perlocutionary acts. Speech acts are commonly taken to include such acts as promising, ordering, greeting, warning, inviting and congratulating.