Speech Act Theory explores how language performs actions beyond conveying information. Developed by J.L. Austin and refined by John Searle, it examines the intended meaning behind utterances and their effects on listeners, considering context, intentions, and social conventions. The theory introduces key concepts like locutionary, illocutionary, and perlocutionary acts, as well as felicity conditions. It categorizes speech acts into assertives, directives, commissives, expressives, and declarations, highlighting the multifaceted nature of language use in everyday communication.