TITLE: Complex grammar in Williams syndrome

This study investigated knowledge of binding and raising in two groups of children with Williams syndrome (WS), 6-12 and 12-16 years old, compared to typically developing (TD) controls matched on non-verbal MA, verbal MA, and grammar. In typical development, difficulties interpreting pronouns, but not reflexives, persist until the age of around 6, while raising is not mastered until about the age of 8 or 9. If grammar in WS is delayed, but develops in a fashion parallel to TD population, similar patterns of difficulties may be expected, although it has not been established whether the grammatical development is ever complete in the individuals with this disorder. Knowledge of the principle of binding which states that a reflexive must have a c-commanding antecedent, was found to be intact in all the participants, in line with previous reports in the literature. In contrast, children with WS younger than 12 showed a poorer performance on personal pronouns, like two groups of younger matched TD controls, suggesting a previously unreported delay in the acquisition of constraints regulating coreferential interpretation of pronouns. Both groups of children with W