Deriving output probabilities in child Mandarin from a Dual-Optimization grammar $

We examine the patterns of optionality that are characteristic of the acquisition of two Mandarin Chinese sentence-final temporal/aspectual markers: inchoative le and progressive ne. What we observe is a productive and systematic pattern of optionality (two forms ne and le for one meaning: inchoative) and ambiguity (one form ne for two meanings: progressive and inchoative) in spontaneous production by three children acquiring Mandarin. We analyze the overuse of ne in child Mandarin as a retreat to a default form that results from an impoverished syntactic representation. We propose an Optimality-Theoretic account in which constraints requiring syntactic realization of the features of the intended meaning “float” in the ranking over constraints that require economy of syntactic structure. These partial rankings characterize a set of alternative grammars that the child uses in production. We propose a Dual-Optimization solution to explain the gap between the children’s production and comprehension of inchoative le and progressive ne.