Traditionally, Nahuatl has been seen as a language with a shallow chronology
and proposed dates for proto-Nahuatl tend to locate it in the early Mesoamerican post-classic period (ca. 800–900 CE). At the same time, the Uto-Aztecan language family has been described as having a rake like structure, with little internal branching. As such, though the development from proto-Uto-Aztecan (ca. 3500 BCE) to proto-Nahuatl is relatively well understood, no intermediate stages have been reconstructed so far. Dakin (1982) proposes a highly useful chronology of phonological changes in the development from proto-Uto-Aztecan to proto-Nahuatl. Nevertheless, some recent findings suggest a need to revise her chronology somewhat, especially because her proposal does not operate with an
intermediate proto-Corachol-Nahuan stage which seems to be necessary
(Pharao Hansen 2020, Greenhill et al. 2023). At the same time a major question in the study of Mesoamerican history, is the question of whether Nahuas (or rather pre-Nahuas) were present in Central Mexico, during the classic period, perhaps with a significant population at the classic period megalopolis of Teotihuacan. Some efforts to read the Teotihuacan writing system has proposed phoneti readings anachronistically using colonial Nahuatl, this however begs the question
of what the pre-Nahuan language would have sounded like in the classic period, during the heyday of Teotihuacan. This paper presents an analysis of the relative chronology of some phonological changes in the development of Proto-Nahuatl from pre- Nahuatl, and their relevance for understanding what pre-Nahuatl might
have been like in the classical period (ca. 200–600 CE) during which the language’s assimilation to the Mesoamerican Language Area must have taken place.