To speak today about predecessors of the indigenous linguistics is to approach the labor of Franciscan missionaries of Nueva España that together with the labor of evangelization tried to systematize the languages of the aborigines with the only aim to teach the Christian doctrine to the Indo-American peoples. The encounter of two worlds brought about the need to communicate between the speakers of different languages and to understand what each other was saying. The way to express themselves demanded an arduous work; it was a slow and complicated process. Pioneers in carrying out this mission were, among others, the missionaries Andrés de Olmos (c.1480-1571) and Alonso de Molina (c.1514-c.1585) who managed to codify the náhuatl.