Spanish colonization occurred during the fifteenth century and played a major role in the decline of the Nahuatl Language. The Spanish conquest of the Aztec empire disrupted not only political systems but also the cultural and social foundations of the Nahua communities.

The Florentine Codex, a historical account created by Bernardino de Sahagun, captures this disruption by showing the fear Nahua communities experienced. Nahua individuals quote, "What are we to do? let it take its course; the time has come when we are to be destroyed. Let us await death here." Furthermore, the Aztec Leader (Moteuccoma) sent messengers, priests, and sorcerers to meet the Spaniards, but ultimately failed, demonstrating a collapse in their religion and culture. This codex demonstrates how colonization created fear throughout Nahua communities and weakened important cultural practices tied to language and identity.      

As Spanish control expanded, Spanish became the dominant language of government, religion, education, and social power, while Nahuatl gradually declined. Over time, this established a social hierarchy that viewed Spanish as more "valuable" socially and economically, while associating Nahuatl as inferior. These colonial attitudes continued to influence schools, public life, and family decisions long after the conquest ended, contributing to Nahuatl’s decline across generations. Even today, the effects of colonization remain visible as Nahuatl continues struggling to survive.