Case marking typology shapes morphosyntactic processing: ERP evidence from Hebrew and Russian monolinguals and bilinguals

This study investigates the neural and behavioral integration of the accusative (ACC) case in Hebrew and in Russian, which differ typologically in case marking: Hebrew employs a prenominal particle, whereas Russian uses postnominal inflections. Experiment 1 examined monolingual Russian and Hebrew speakers, and Experiment 2 tested Russian-Hebrew bilinguals, heritage Russian speakers dominant in Hebrew. Participants (N = 117) completed an auditory acceptability judgment task during EEG recording. ERPs were time-locked to the case-marking position in grammatical and ungrammatical ACC constructions (double nominative, double ACC). Hebrew monolinguals showed graded judgments and P600 effects for both violation types. Russian monolinguals showed categorical judgments and early sMMN and P300 effects only for double ACC violations. In Hebrew, bilinguals demonstrated monolingual-like behavioral sensitivity and early ERP effects. In Russian, bilinguals differed from monolinguals behaviorally and neurally, showing less categorical responses yet larger P300 effects. These findings indicate that typological differences and bilingual dominance shape morphosyntactic processing.