Until his return from Mexico in 1930 Whorf had been entirely an autodidact in linguistic theory and field methodology, yet he had already made a name for himself in Middle American linguistics. Whorf had met Sapir, the leading US linguist of the day, at professional conferences, and in 1931 Sapir came to Yale from the University of Chicago to take a position as Professor of Anthropology. Alfred Tozzer sent Sapir a copy of Whorf's paper on "Nahuatl tones and saltillo". Sapir replied stating that it "should by all means be published"; however, it was not until 1993 that it was prepared for publication by Lyle Campbell and Frances Karttunen.