German, Greek, Russian, and Turkish represent typologically different (non-)null subject languages. Greek is a consistent pro-drop language, Russian is characterized as a partial or non-pro-drop language with frequent subject ellipsis, and Turkish is a topic pro-drop language where overt subjects are typically required in ambiguous contexts. German, by contrast, is traditionally classified as a non-pro-drop language, with subject pronouns generally required in finite clauses. However, it exhibits topic-drop in informal registers (Fries, 1988) and under certain grammatical constraints (Trutkowski, 2016). While often perceived as sub-standard, topic-drop in German has been argued to be a canonical feature (Schäfer, 2021).
Prior research has documented increased use of overt subjects in heritage varieties of Greek, Russian, and Turkish (Dubinina & Polinsky, 2013; Haznedar, 2010; Tsimpli et al., 2004), but comprehensive crosslinguistic comparisons across registers and modalities remain limited. Research on heritage bilinguals has largely focused on transfer from the majority language to heritage languages, leaving understudied the reverse: how typologically null-subject heritage languages may influence subject realization in majority German.
In this study, we examine subject-drop in a corpus of naturalistic spoken and written data from more than 400 monolingual and bilingual speakers of German, Greek, Russian, and Turkish. Using Bayesian binomial generalized linear mixed-effects models, we investigate crosslinguistic effects in both directions. Our results reveal increased overt subject use in heritage Russian and Turkish, but not in heritage Greek. These effects are modulated by register and modality, suggesting varying degrees of persistence in null subject realization linked to the typology of the heritage language. An animacy effect—where animate subjects are more likely to be dropped—was consistent across all language pairs. In majority German, however, subject-drop patterns were similar across all bilingual groups, indicating that bilingualism per se does not lead to increased topic-drop. Instead, language status (heritage vs. majority) emerges as the key factor influencing subject expression. These findings highlight the complex interplay between typological properties, register, and bilingual language use in shaping null subject behavior across bilingual populations.
