Syntax in Spanish-speaking children with Williams syndrome

•Children with Williams syndrome perform worse than their peers matched in chronological age in all tasks.•Compared to their peers matched in verbal age they perform worse only in sentences containing cross-serial dependencies.•They are more sensitive to semantic cues than to syntactic constraints.•The exhibit a poorer lexical knowledge of some functional words (specifically, of non-reflexive pronouns).•A processing bottleneck or a computational constraint may account for this outcome.

The syntactic skills of Spanish-speaking children with Williams syndrome (WS) were assessed in different areas (phrase structure, recursion, and bound anaphora). Children were compared to typically-developing peers matched either in chronological age (CA-TD) or in verbal age (VA-TD). In all tasks children with WS performed significantly worse than CA-TD children, but similarly to VA-TD children. However, significant differences were observed in specific domains, particularly regarding sentences with cross-serial dependencies. At the same time, children with WS were less sensitive to syntactic constraints and exhibited a poorer knowledge of some functional words (specifically, of nonreflexive pronouns). A processing bottleneck or a computational constraint may account for this outcome.