Word knowledge is critical for speaking, reading and writing, yet a substantial proportion of children with language impairment demonstrate poor word learning and consequently poor vocabulary. Because vocabulary has a causal relationship with reading comprehension, this presents a significant national health concern. To develop effective interventions, we require a clear understanding of the deficits underlying poor word learning. Deficits in short-term phonological memory have been implicated as a causal factor in poor word learning; however, phonological memory measures accounts for a limited amount of variance associated with word learning. In this project we investigate the underlying causes of poor word learning attributable to working memory using two newly developed working memory and word learning batteries useful for research and clinical practice.
(1) Model working memory and word learning performance in monolingual English-speaking children with typical development (TD);
(2) Compare working memory and word learning performance in bilingual Spanish-English children with TD to monolingual English-speaking children with TD;
(3) Compare working memory and word learning performance in monolingual English-speaking children with specific language impairment (SLI), dyslexia, and comorbid SLI/dyslexia to monolingual English- speaking children with TD;
(4) Develop a unified working memory-based word learning model;
(5) Determine whether working memory-based word learning subtypes exist within the typically- developing monolingual English, bilingual Spanish-English, SLI, dyslexia and SLI/dyslexia groups;
(6) Finalize an efficient working memory-based word learning battery useful for research and clinical assessments.