Input Effects on the Acquisition of Finiteness

Gradual Morphosyntactic Learning (Rispoli & Hadley, 2011; Rispoli, Hadley & Holt, 2012) hypothesizes that children benefit from diversity in parent input and it also posits cross-morpheme facilitation, whereby learning one morpheme facilitates the acquisition of others. Thus, diversity in parent input for copula is should facilitate the acquisition of verb-s. 42 children were observed at 21, 30, and 36 months. A copula is input TTR was computed from parent input to children at 21 months, and this was positively correlated with child copula is productivity at 30 months. Children's accuracy in marking verb-s and past tense was assessed at 36 months with standardized probes (Rice & Wexler, 2001). Hierarchical multiple regression analyses revealed that parents' copula is input TTR accounted for unique variance in children's verb-s accuracy scores, but not verb past tense.