This Proto-Nahuan entry contains reconstructed terms and roots. As such, the term(s) in this entry are not directly attested, but are hypothesized to have existed based on comparative evidence.
Campbell, Lyle, Langacker, Ronald W. (October 1978) “Proto-Aztecan Vowels: Part III”, in International Journal of American Linguistics, volume 44, number 4, pages 262–279: “(191) who *aak”