Phrase Structure Grammar is a type of grammar that breaks down sentences into smaller parts called phrases. Each phrase has a specific structure, which helps to understand how words combine to form meaningful sentences. For example, a simple sentence can be divided into a noun phrase and a verb phrase, showing how subjects and actions relate to each other. This approach uses rules to describe how phrases can be formed and combined. These rules often involve symbols and diagrams, making it easier to visualize the relationships between different parts of a sentence. Noam Chomsky is one of the key figures associated with this theory, influencing how we study language.