Williams Syndrome: A Case Study of Early Lexical and Morpho-Syntactic Development
Peggy Jacobson, Department of Speech, Communication Sciences and Theatre, St. John’s College of Liberal Arts and Sciences
Williams syndrome (WS) is a rare genetic disorder characterized by an uneven profile of cognitive and linguistic development. Despite mild to moderate mental retardation, individuals with WS demonstrate relatively good communication skills. This is a case study of a child with WS who was followed from approximately 1 1/2 to 6 years of age. Current reports of language ability in WS yield conflicting results. Some report exceptional challenges with respect to irregular morphology, while others report irregular forms that are consistent with an overall language delay. By monitoring early lexical and morph-syntactic development using standard vocabulary measures, language samples, and elicited production of past tense forms, early patterns that related to later difficulties were revealed. Specifically, early lexical deficits were consistent with a persistent difficulty in acquiring irregular forms. These results are discussed within the framework of a dual mechanism account of regular and irregular verb production.