This document provides an overview of speech act theory. It discusses that speech act theory attempts to explain how speakers use language to accomplish intended actions and how listeners determine intended meaning. It was first proposed by J.L. Austin and later expanded on by John Searle. The document then discusses key aspects of speech act theory, including locutionary, illocutionary, and perlocutionary acts. It also discusses felicity conditions and provides an example of the speech act of promising. Finally, it provides a brief overview of John Searle's contributions to the development of speech act theory.