Sentence Repetition as an Ecologically Valid Tool for Assessing Bilingual Children’s Language Abilities: The Role of Morphological Awareness and Expressive Vocabulary

This study examined the value of Sentence Repetition (SRep) tasks as an ecologically valid tool for assessing bilingual children’s morphosyntactic competence. Seventy Greek–Turkish bilinguals and Greek monolinguals (aged 8–12) completed tasks assessing expressive vocabulary, morphological awareness, and SRep. Monolinguals significantly outperformed bilinguals across all tasks, with near-ceiling scores in grammaticality in SRep tasks reflecting earlier acquisition of core Greek structures. In contrast, bilinguals’ performance was significantly lower and varied across conditions: while scores were relatively higher on simple SVO, coordination, and wh-clauses, difficulties emerged in clitic left dislocation, complement clauses, and adverbial clauses—domains of greatest typological divergence between Greek and Turkish. Importantly, SRep performance on grammaticality did not vary with age, despite strong age effects on vocabulary and morphology, suggesting that SRep tasks indexes morphosyntactic knowledge rather than general maturational growth. Regression analyses showed that monolinguals’ SRep performance was best predicted by morphological awareness, whereas bilinguals relied more heavily on expressive vocabulary, reflecting their reduced exposure to Greek and reliance on lexical resources. These findings confirm the fairness and sensitivity of SRep for bilingual assessment, while highlighting the interplay of typological differences and input in shaping bilingual children’s morphosyntactic abilities.