Uto-Aztecan languages
In addition, Pilling had compiled much of the material for a proposed bibliography of Mexican languages, which was not published during his lifetime. Now known as the Uto-Aztecan languages, their kinship was conclusively established by Edward Sapir in the 1920s, but Powell had opposed such a classification scheme. Pilling's Shoshonean languages are now known as Northern Uto-Aztecan, while his Sonoran and Aztec groupings are now both considered among the Southern Uto-Aztecan languages.