Children's and adults' eye movements and the extraction of number information from ambiguous and unambiguous markings

Children learn to extract number information from utterances using a variety of language-specific cues, but in some languages this information is encoded in features that display high variability in their realization. How does this affect their acquisition process? In this paper, we present an eye tracking study comparing 3.5- to 7.5-year-old children and adults' use of number information on the verb and the determiner of the subject noun phrase in Chilean Spanish, a dialect of Spanish with variable realization of plural morphology in the noun phrase (due to phonological weakening) and categorical realization of number on the verb. Our results suggest that, while adults can determine whether the subject refers to a plurality or a singleton set based on the morphology of the verb alone, even 5- to 7.5-year-old children do not and, instead, require information from the noun phrase determiner to make a decision. Children younger than 5 years, instead, cannot use number information on the verb and on the determiner to make a decision. This supports Miller and Schmitt's (2010, 2012) hypothesis that number morphology is not always mapped into syntactic and semantic features by younger children in varieties of Spanish where number is subject to variation.