Adaptive language strategies of an older sibling in bilingual German-Russian acquisition: A case study

Abstract In the beginning stages of language acquisition, children primarily learn language from their parents or main caregivers. Studies have shown that adults use a specific way of speaking when talking to young children, called child-directed speech (CDS). This type of speech has distinct characteristics across different aspects of language. Additionally, older siblings also communicate with their younger brothers and sisters. Studies suggest that even three- and four-year-olds change how they talk when interacting with younger children, like their siblings. Studies have shown that children’s speech patterns resemble those of adults, whether they grow up in monolingual or bilingual environments. However, research on bilingual language acquisition often focuses on how siblings influence the language development of younger children. In this study, we explore how children adapt their language in bilingual settings and focus on the older sibling. Specifically, we compare the speech of an older sibling, who speaks both German and Russian, when talking to their younger sibling and when talking to their parents. The study revealed the following: The girl demonstrated linguistic adaptations typical of child-directed speech in both Russian and German when interacting with her younger brother. However, these adaptations were not consistent across all linguistic categories analyzed, revealing some differences between the two languages. Notably, Katharina did not exhibit more child-directed speech features in one language over the other. Adaptive behavior was present in both Russian and German in categories such as MLU, MLU5, question constructions, and imperatives. In Russian, adaptation was also evident in coordinate constructions but not subordinate constructions, while the opposite pattern was observed in German.