Effects of Input Consistency on Children’s Cross-Situational Statistical Learning of Words and Morphophonological Rules

Children learn linguistic structures from the input they receive. Their learning may depend on several factors such as children’s sensitivity to structure in the input, prior language experience, and the consistency of linguistic structures in the input. In this study, we investigated how inconsistent input (i.e., substitution errors) in an artificial language affects 7 to 11-year-old Dutch-speaking children’s learning of words and rules. Using a cross-situational statistical learning task (CSL task), we assessed children’s learning of label–referent pairs (word learning) and their generalization of two morphophonological rules. Eighty-nine children were randomly allocated to three input conditions: a fully consistent input condition (n = 31), a 12.5% inconsistent input condition (n = 32), and a 25% inconsistent input condition (n = 26). In the inconsistent input conditions, children were exposed to substitution errors, respectively, 12.5% and 25% of the time. We found evidence that substitution errors in children’s language input hindered their cross-situational statistical language learning. While we have evidence that children learned the words in our artificial language, we have no evidence that children—regardless of input condition—detected the morphophonological rules. This study eventually may inform us on how differences in the quality of children’s language environments (arising from, e.g., speaker variability and language proficiency) affect their language learning.