Out of the mouths of babes: children and the formation of the Río de la Plata Spanish address system

Abstract This paper analyzes the effects of child language acquisition as a critical factor in a morphological change, namely, the replacement of the etymologically singular second person paradigm ( tuteo ) by its plural counterpart ( voseo ) in 19th century Río de la Plata Spanish. The account applies a sociohistorical model which proposes that young children can function as language change agents in environments characterized by unpredictable input variation, lack of normative mechanisms, and the emergence of peer networks among young learners. The model is then applied to explain the rapid generalization of voseo in the late 1800s, a well-documented but poorly understood process. This change was nestled in an environment characterized by the rapid breakdown and reshaping of social networks through country-to-city migration and massive immigration, and by the resulting contact between L1 and L2 speakers of Iberian and non-Iberian varieties. Our account hypothesizes that successive cohorts of children actuated the various stages of this change, by relying on child language acquisition biases in the learning of verbal morphology observed across Romance varieties. This study combines archival evidence and sociohistorical information with present-day acquisitional data. The latter offers a piece often missing in sociohistorical accounts of language change.