This book is about various linguistic aspects and consequences of the effective colonization of Latin America by Portugal and Spain since the dawn of the 16th century. It is about how Portuguese and Spanish (then known only as Castilian) have both been influenced by their contacts with indigenous and other languages in their Iberian colonies, as well as how the indigenous languages in particular have also been affected by the colonial languages. The book provides novel perspectives onto how the European colonists first communicated with the Natives, onto the role played by the “factors,” missionaries, Mestizos, and Pardos as interpreters, and onto why one should not assume that jargons or pidgins emerged of necessity out of the initial inter-group contacts. Insights are likewise provided about the gradual ways in which Portuguese and Spanish spread, about how some major indigenous languages (such as Quechua and Tupinambá) at first benefited from the European colonization and from their adoption by missionaries as lingua francas for proselytizing, as well as about why some Native American languages are being threatened only now or don't appear to be (seriously) endangered yet. Throughout the volume, one has to ask who have been the actual agents and/or drivers of the changes that have affected both indigenous and initially exogenous languages, positively or negatively, in Latin America. And what are the relevant ecological factors that have triggered or simply borne on these evolutions? The subject of African substrate influence is also dealt with, alongside that of Italian adstrate influence on Argentine Spanish.