Sor Juana composed two known pieces that incorporate the Nahuatl language. These have often been studied in terms of their relationship to the villancico form or as either progressive or conservative renderings of the linguistic and racial diversity of seventeenth-century New Spain. This article takes a different approach to the Nahuatl compositions, placing them in dialogue with the attempts by sixteenth-century missionaries to compose poetry in that language for the purposes of evangelization. In this way, we can see how Sor Juana subtly reflects on and ironizes the limits of intelligibility in a colonial context.