The history of linguistics in the United States begins with William Dwight Whitney, the first U.S.-taught academic linguist, who founded the American Philological Association in 1869. The history of linguistics in the United States begins with William Dwight Whitney, the first U.S.-taught academic linguist, who founded the American Philological Association in 1869. Leonard Bloomfield (1878–1949), professor at the University of Chicago from 1921, founded the Linguistic Society of America in 1924. Other linguists active in the first half of the 20th century include Edward Sapir and Benjamin Whorf. From the 1950s, American linguistic tradition began to diverge from the de Saussurian structuralism taught in European academia, notably with Noam Chomsky's 'nativist' transformational grammar and successor theories, which during the 1970s 'linguistics wars' gave rise to a wide variety of competing grammar frameworks. Noam Chomsky is an American linguist who is often described as the 'father of modern linguistics'. He theorized on language from a biological standpoint, and referred to it as a cognitive ''module'' in the human brain. Chomsky outlined key differences between language cognition in humans and in other animals as head author of 'The Language Faculty', published in 2002. He also contributed the theory of Universal Grammar. American linguistics outside the Chomskyan tradition includes functional grammar with proponents including Talmy Givón, and cognitive grammar advocated by Ronald Langacker and others. John McWhorter, who has a background in teaching African-American studies, is another American linguist. Linguistic typology, and controversially mass lexical comparison, was considered by Joseph Greenberg. Historical linguistics, especially Indo-European studies, is taught widely in the United States.