 He concludes that based on children's increasing rate of homogeneous parts-of-speech answers with age in conjunction with the answers they give to the "Usage Test" are two ways children can be observed to develop an appreciation of English syntax.Thus, supporting a theory that language acquisition is a maturational process.Linguistic Determinism and the Part of Speech (1957)

In 1957, Brown sought to figure out how language constitutes perception and thought of one's surroundings.