Individual differences in language learning inform us about the neurocognitive mechanisms involved in language acquisition.  A fundamental question in language acquisition asks if language acquisition utilizes a general purpose learning mechanism or if dedicated cognitive mechanisms exclusive to language learning are needed. My research focuses on identifying general purpose cognitive (i.e. domain general) mechanisms underlying individual differences in the ability for language learning. My particular focus has been comparisons between children with typical language development (TD) and children with developmental language disorder (DLD). Children with DLD exhibit difficulties in the development of spoken language without any frank disability that would explain their difficulties. Although the cause or causes of DLD are unknown, heritability estimates suggest genetic contributions. While some candidate genes have been identified, the progress has been erratic, perhaps because diagnostic categories like DLD are likely to be heterogeneous with different genetic and environmental underlying factors contributing to the heterogeneity. Identifying measures of underlying cognitive markers together with environmental risk factors is likely to allow a more accurate examination of neural developmental processes and genes contributing to this disorder as well as individual differences in language development. My research has directly provided evidence for several domain general cognitive markers that are related to individual differences in language development.

In addition to informing theories of language development and DLD, my research makes a difference in the society. The scientific findings of our studies help better identify language learning impairments in children. Large scale studies have indicated that even though childhood language impairments have significant negative academic, social, employment and mental health consequences, DLD often remains undiagnosed and untreated. I have been part of an interdisciplinary international CATALISE (Criteria and Terminology Applied to Language Impairments: Synthesizing the Evidence) consensus panel, which recently came out with recommendations for new evidence-based terminology and diagnostic criteria for identifying childhood language impairments (Bishop et al. 2016; 2017).  The nonverbal cognitive and motor deficits present in DLD my research has provided evidence for were recognized as a part of the language disorder profile and the new term developmental language disorder was recommended. Some of these recommendations were immediately reflected on the new ICD 11 (International Classification of Diseases 11th Revision).