Answer
Uto-Aztecan, the answer, is a prominent language family indigenous to the Americas, primarily spoken in regions of the United States and Mexico. This language family encompasses over 30 languages, including well-known tongues such as Nahuatl, spoken by the Aztecs, and Hopi, spoken in parts of the American Southwest. Whorf's contributions lie in reconstructing aspects of the Uto-Aztecan family, shedding light on its historical development and relationships among its various languages.