Speech act theory is a foundational concept in the philosophy of language and linguistics that examines how language is used to perform actions rather than simply state facts. It analyzes the illocutionary force of utterances, investigating the speaker's intention and the type of act being performed (e.g., promising, questioning, commanding) beyond their literal semantic content. This theoretical framework is significant for understanding the pragmatic functions of communication and the dynamic relationship between language, context, and speaker intention.