In Turkish, definiteness is marked through accusative case marking -(y)I and the presence or absence of the prenominal determiner bir (one). Crucially the latter may function as an indefinite determiner depending on the context. Previous studies have shown that definiteness is a vulnerable phenomenon for Turkish heritage speakers, as they have to integrate different language modules (e.g., morphosyntax and discourse/pragmatics). This study tested 49 monolingual Turkish speakers from Türkiye and 32 heritage speakers from the USA via an acceptability judgment task. Twenty-three of the heritage speakers were first-generation, and nine were second-generation heritage speakers. The experimental stimuli were created by manipulating both the grammatical number of the object (singular bir kitap ‘one/a book’ vs. plural kitap-lar ‘books’) and whether the object was preceded by a numeric determiner (bare kitap ‘a book’ vs. non-bare beş kitap ‘five books’) to test the acceptability of the nominal’s correct definiteness marking in a subsequent sentence. The results indicate significant discrepancies between the first- and second-generation heritage speakers, indicating crucial transgenerational variation in the use of the correct form of Turkish definiteness, while the first-generation and monolingual speakers do not differ from each other. These findings suggest that the integration of morphosyntax and discourse/pragmatics in definiteness marking, a particular aspect of linguistic competence within theorizing in generative grammar, does not seem to be fully acquired by second-generation heritage speakers as a result of acquiring Turkish under heritage language conditions.
Uygun et al. (Tue,) studied this question.