Origins of contact varieties are at the center of language contact research, focusing on the dynamics between the population structure’s social ecology and the linguistic phenomena that emerge. This chapter proposes an alternative hypothesis to the emergence of Andean Spanish, a macro-dialect spoken in several countries in western South America and product of contact between Spanish and Andean languages, particularly Quechua, the most spoken in the Americas. It argues that contrasts between the linguistic evidence present in colonial documents authored by Indigenous individuals and those present in the speech of Andean Spanish speakers in the twentieth and twenty-first centuries reveal different types of contact phenomena. The colonial data include linguistic evidence of lexical borrowing (primarily cultural) and grammatical phenomena proper of second language speakers (e.g., number and gender agreement, vocalic alternation). The post-colonial data include evidence of grammaticalization phenomena, revealing a case of contra-hierarchical grammatical influence (from the minoritized Indigenous language to the hegemonic language). The contrast between these two historical periods’ internal social ecologies reveals specific (types of) social conditions that help explain the focusing and emergence of the contact (macro-)dialect known as Andean Spanish.