Naar effectieve en efficiënte taaldiagnostiek. Het onderscheid tussen tweetaligheid en taalontwikkelingsstoornis

Accurately distinguishing typical bilingual language development from developmental language disorder (DLD) is a persistent challenge in multilingual contexts. Limited exposure to the societal language and cross-linguistic transfer can resemble DLD-related difficulties, increasing the risk of misdiagnosis. This dissertation aims to improve diagnostic accuracy and efficiency for bilingual children by integrating conventional behavioural measures with exploratory, language-independent approaches. Five studies were conducted with bilingual children with and without DLD. A data-driven analysis in study 1 identified a small set of behavioural measures—sentence repetition, parental ratings of home language proficiency, nonword repetition, and receptive language skills—that accurately differentiated DLD from typical development while remaining feasible in clinical settings. Studies 2 and 3 examined narrative abilities. Quantitative metrics of productivity, complexity, and accuracy, complemented by qualitative error analyses, reliably distinguished DLD from typical bilingual development. Morphological and syntactic error patterns were particularly diagnostic of DLD. To address the limitations of Dutch-dependent assessments, studies 4 and 5 explored innovative approaches. A nonverbal gesture comprehension task differentiated DLD from TD children regardless of language background, while an EEG-based neural tracking paradigm demonstrated sensitivity to comprehension in both societal and home languages. Together, these studies highlight the value of combining efficient behavioural tools with emerging multimodal methods to support equitable and evidence-based diagnosis of DLD in bilingual children.