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”