A speech act is a linguistic utterance that serves a communicative function. Speech acts can range from single words like apologies to longer statements. They require knowledge of both language and appropriate cultural usage. Common types of speech acts include greetings, requests, complaints, invitations, compliments, and refusals. Cultural understandings of speech acts can differ, such as whether "I agree with you" is a compliment or not. Pragmatic competence involves understanding the intended meaning, or illocutionary force, of an utterance in context. A perlocutionary act is the effect achieved by a speech act, whether intended or not.