Across Europe and globally, increasing numbers of children and adolescents grow up using more than one language. Many of these individuals are heritage language speakers: they are exposed to a minority or family language at home while receiving most of their education and social input in the majority language. Although heritage speakers are often highly functional bilinguals, their language abilities show substantial individual variation, and the reasons for this variability remain poorly understood.
Most previous research on heritage languages has focused either on adults or on outcomes measured through tests completed after language use has taken place (for example, written judgments or questionnaires). As a result, much less is known about how heritage languages are processed in real time, especially during adolescence — a developmental stage that is both socially and cognitively crucial. This gap limits our understanding of how language experience, cognitive factors, and development interact, and it risks oversimplified views of bilingual language competence.
The project addressed this gap by examining how adolescent heritage speakers process language moment by moment, focusing on Mandarin as a heritage language. Its core objective was to identify when, how, and under what conditions individual differences matter during language processing. Rather than treating heritage speakers as a uniform group, the project aimed to understand variability as a meaningful and systematic feature of bilingual language use.
To achieve this, the project combined approaches from the social sciences and humanities, particularly linguistics, psychology, and cognitive neuroscience. It used time-sensitive experimental methods that track language processing as it unfolds, allowing the study of comprehension dynamics rather than only final answers. By integrating detailed measures of language experience with real-time processing data, the project adopted a pathway to impact that links fundamental theory with socially relevant questions about multilingual development.
The project’s expected impacts include advancing scientific understanding of bilingualism, challenging deficit-based views of heritage language competence, and providing a stronger evidence base for discussions about linguistic diversity in multilingual societies. In the longer term, insights from this work can support more informed educational, societal, and policy-related conversations about bilingual development, language maintenance, and inclusion in Europe’s linguistically diverse communities.
