Prior to colonization, diverse Indigenous populations across the area now known as Mesoamerica developed complex writing systems. In this dissertation, I examine Postclassic Mesoamerica as a time and place with shared knowledge that spanned across regions inhabited by diverse linguistic groups. During this time, the Nahuatl language served as a spoken lingua franca, and the Mixteca-Puebla writing style (used by Nahuatl speaking people) served as a written lingua franca. As such, my approach makes these glyphic texts (such as the Codex Borgia and other Borgia Group codices) and alphabetic Nahuatl texts (such as the Florentine Codex and the Codex Chimalpopoca) central to the understanding of indigenous culture. Using this approach, I begin by reexamining the ways that previous translations of texts have diminished the role of women within society, and specifically the role of women as readers and writers of diverse texts.

I then shift my focus to these texts, challenging the view that they often function as ideograms not tied to a spoken language. I accomplish this by redefining what constitutes writing according to the Nahuatl texts, and proposing the presence of logographic and phonographic writing within the Codex Borgia. I develop a method of decipherment for Codex Borgia pages 49 through 54, using Codex Borgia page 51 (CB51) as a case study. Within this case study, I examine the nature of teotl in Mesoamerican religious traditions, and specifically address the roles of Mayahuel and maguey, as seen in both the alphabetic and glyphic texts. In so doing, I challenge the current identification of the central tree on CB51 as a young corn tree, arguing instead that it represents the teotl Mayahuel/maguey.

I extend these methods of decipherment across Codex Borgia pages 49 through 54 to argue that these pages contain glyphs and iconography suggestive of the narratives of the teotl Tlahuizcalpanteuctli, Lord of the Dawn and an embodiment of the planet Venus. Furthermore these glyphs and iconography on CB49 through CB54 suggest the presence of a Venus Table that records the dates associated with the four stages of Venus within its synodic period: Venus as the Morning Star, its first period of invisibility, Venus as the Evening Star, and a second period of invisibility. I conclude my investigation with a translation and analysis of the narrative of Topiltzin Quetzalcoatl, the historical religious and political leader from Tollan who transformed into Tlahuizcalpanteuctli. I examine the role of Topiltzin Quetzalcoatl as the archetype for tlamacazque (people within the precontact religious order), and the events that led him to leave Tollan.

Through an examination of the use of kinship terms in alphabetic Nahuatl texts, I challenge academic readings of Topiltzin Quetzalcoatl as an incestuous figure. The goal of this complete work is to serve as a decolonial project wherein the indigenous writers' voices can become central in our analyses and understandings of these and other indigenous cultures.