The $2000 clue: This Japanese-American professor of linguistics was a California senator from 1977 to 1983.
The answer: S.I. Hayakawa
Samuel Ichiye Hayakawa (July 18, 1906 – February 27, 1992) was an important figure in the field of semantics. His 1949 book Language in Thought and Action helped popularize the study of semantics.
Clue from Jeopardy episode #5448, aired 2008-04-23