Case Marking in Turkish Heritage Children With and Without Developmental Language Disorder

Recent studies on agglutinative languages, such as Japanese, Finnish, and Turkish, have reported case marking deficits in children with developmental language disorder.In this study, we investigate case marking in bilingual children speaking Turkish as a heritage language in Germany in comparison to those in France and the U.S. and late successive bilinguals in Germany. The research focuses on the potential use of case marking to identify developmental language disorder in Turkish as a heritage language. In this study, we compare data obtained from 73 children with and without developmental language disorder (age 5;1-11;6) that speak Turkish as a heritage language to those obtained from 10 late successive bilinguals (age range 7;12-12;2) in Germany, France, and the U.S., analyzing case marking and the possessive markers included in genitive-possessive constructions and using both standard and heritage Turkish as reference varieties. The results show that the groups differ significantly (p < 0.05) regarding the use of case and possessive markers. Current first language use is the leading predictor of performance in case marker production in the TED & Idot;L when using heritage Turkish as the reference variety in scoring. The results demonstrate that children with developmental language disorder that speak heritage Turkish produce fewer case markers and show higher rates of omission and substitution errors, particularly in accusative/dative and genitive markers, thus confirming the results of previous research. The omission of possessive and genitive markers in simpler structures may serve as a clinical marker of developmental language disorder, allowing for children with typical language development that speak heritage Turkish to be distinguished from those with a developmental language disorder.