Lexical Processing and Executive Function in Bilingual Children with and without Language Disorder

The study of bilingualism and its interaction with Developmental Language Disorder (DLD) in children has often led to divergent theories and perspectives. This dissertation presents a comprehensive investigation into this complex interplay, employing a combination of behavioural analyses and Event-Related Potentials (ERPs). Across three distinct studies, it examines cognitive control, lexical processing, and executive functions in bilingual and monolingual children, both with and without DLD. Study 1 reexamines the widely accepted notion of a bilingual cognitive advantage. It unveils that bilingual children face distinct processing challenges, marked by prolonged reaction times and unique neural patterns, especially when encountering unfamiliar lexical stimuli. These findings illuminate the intricate cognitive processing dynamics inherent in bilingual contexts, challenging existing perceptions and adding depth to our understanding of bilingual cognition. Study 2 shifts focus to bilingual children with DLD, juxtaposing their abilities with those of typically developing bilingual peers. Contrary to the prevalent belief that bilingualism intensifies language disorders, the study reveals a nuanced, facilitative role of bilingualism in processing familiar lexical items, offering a fresh perspective on bilingual language development. Study 3 furthers this exploration by comparing bilingual and monolingual children with DLD. It discovers that while bilingualism introduces specific challenges in processing unfamiliar words, it does not invariably exacerbate cognitive control or familiar word processing difficulties. Collectively, these studies forge new paths in understanding the dynamic interplay between bilingualism and DLD. They propose that bilingualism can present both challenges and potential advantages in cognitive and linguistic development, compelling a revaluation of long-standing paradigms. This dissertation not only challenges established beliefs but also emphasizes the importance of considering individual linguistic experiences and cognitive strategies in deciphering bilingualism's role in language disorders. This work highlights the multifaceted nature of bilingualism and DLD, advocating for a more comprehensive and individualized approach in this evolving field.