SFB1287_B04_Constraints on subject-verb agreement marking in Turkish-German bilingual speakers

Turkish 3rd person plural subjects normally appear with verbs that are unmarked for number. Following earlier findings which indicate that Turkish heritage speakers (HS) accept overt plural marking more readily compared to monolingually raised Turkish speakers, the present study investigates to what extent bilingual speakers are sensitive to grammatical, surface-level and semantic constraints on Turkish plural agreement marking. A scalar acceptability judgement task was carried out with non-bilingual Turkish speakers residing in Turkey and Turkish-German bilinguals residing in Germany. Our experimental design involved manipulating both subject animacy and subject position. Participants' judgement patterns confirmed Turkish speakers' general preference for unmarked verb forms, which was modulated both by subject animacy and by subject position. Significant differences were observed between lower proficiency HS on the one hand, and monolinguals and advanced proficiency HS on the other, suggesting that the relatively subtle interplay between different types of constraint on number agreement marking is affected by heritage language conditions. We found no evidence for simplification or optionality reduction in the lower proficiency HS' judgements, however. We innovate on previous research by using Gradient Symbolic Computation modelling to capture between-group differences in the relative weightings of the constraints under investigation.

土耳其语中，第三人称复数主语通常与未标记数量的动词搭配。继先前的研究发现，土耳其语母语者（HS）相较于单语土耳其语使用者，更易于接受显性复数标记之后，本研究旨在探讨双语使用者对土耳其语复数一致标记的语法、表层结构和语义约束的敏感性程度。本研究对居住在土耳其的非双语土耳其语使用者和居住在德国的土耳其-德语双语者进行了标度可接受性判断任务。我们的实验设计包括操纵主语的生命性和主语位置。参与者的判断模式证实了土耳其语使用者普遍倾向于未标记的动词形式，这种倾向既受主语生命性的影响，也受主语位置的影响。在低熟练度的HS、单语使用者以及高级熟练度HS之间观察到显著的差异，这表明不同类型数量一致标记约束之间的相对微妙互动受到母语条件的影响。然而，我们在低熟练度HS的判断中并未发现简化或选项性降低的证据。我们通过使用梯度符号计算建模创新性地对先前研究进行了研究，以捕捉研究中的约束在组间相对权重上的差异。