Joseph Greenberg was an influential American linguist, best known for his work in the field of historical linguistics. He was born on May 28, 1915, and passed away on May 7, 2001. Greenberg is particularly recognized for his theories on language classification and his contributions to the study of language universals, which explore the common features shared by all human languages. One of his significant contributions was the proposal of the Greenberg's classification, which grouped languages into families based on shared characteristics. He also conducted extensive research on the languages of Africa, contributing to the understanding of the Niger-Congo language family. His work has had a lasting impact on the study of linguistics and continues to influence researchers today.