(from Yule, 1996)
When we express ourselves, we don’t simply produce utterances made up of grammatical structures and words; we are actually performing specific actions through those utterances. Those actions are the communicative intentions we have when we speak or write—how we want our words to be interpreted by our interlocutors.
Speech acts describe the speakers’ (or writers’) communicative intentions when they say (or write) something. They can be further classified into specific communicative intentions, such as making a request (Could you close the window, please?), refusing (I’d love to go with you, but I my doctors’ appointment is at the exact same time…), apologizing (I’m sorry for not texting you earlier.), complimenting (You did such a great job today!), thanking (How can I ever repay you?), complaining (Oh, yesterday’s class was the absolute worst!), inviting (How about going out to dinner with me tonight?), among others.
The speaker/ writer normally expects that the hearer/reader recognizes the communicative intention of the utterance. One aspect of communication that contributes to the hearer’s correct interpretation of the speech act being performed (the speaker’s communicative intention) is the situational context; that is, the circumstances under which the utterance was performed, which Yule (1996, p.47) calls speech events.