His grammar contained also the earliest known Quechua written text, as a catechetic appendix, and the first known linguistic description of clusivity.

After he was ordained as a priest and had served in Spain for years, he was assigned as a missionary to the Spanish colonial Viceroyalty of Peru in 1540, soon after the initial conquest of 1533.

For the purpose of Indian Reductions, by which the Spanish brought natives together around missions for teaching and work, Domingo learned the Quechua dialect that was spoken along the Peruvian coast near Lima.

The coastal dialect of Quechua was significantly different from the one in Cuzco, as was detailed by Diego González Holguín in the early 17th century.

In the same year, he published his Lexicon, o Vocabulario de la lengua general del Peru.