Generative grammar was developed by Noam Chomsky in the mid-20th century.
While Hayakawa was a renowned linguist and semanticist, his work focused primarily on the study of meaning and communication. He is best known for his contributions to General Semantics.
Generative grammar, on the other hand, is a theoretical framework for understanding the structure of language and how it is generated by the human mind. It focuses on the underlying rules and principles that govern the formation of sentences.