A comparative study of heritage vs. non-heritage Chinese learners across proficiency levels during study abroad

Existing literature has documented heritage speakers' (HSs) linguistic advantages and the benefits of study abroad (SA) in second language acquisition, yet empirical research on HSs' oral development during SA remains limited. This 16-week study tracked oral development among 44 learners of Chinese varying in heritage status (21 HSs, 23 non-heritage speakers [NHSs]) at low-intermediate and high-intermediate levels during SA in China. Oral data collected at four time points were analysed via Complexity, Accuracy and Fluency (CAF) measures. SA immersion significantly improved most CAF dimensions for all learners. Group differences were primarily moderated by proficiency level rather than heritage status: high-intermediate learners showed significant group-by-time interactions in fluency and lexical production, whereas low-intermediate learners exhibited parallel developmental paths except for lexical diversity (TTR) and syntactic complexity. HSs demonstrated more stable lexical diversity, while NHSs achieved greater gains in fluency, lexical output and syntactic complexity. These results highlight the selective, dimension-specific effects of heritage status and the role of proficiency in shaping oral development in immersive settings. The study also identifies a potential “heritage speaker trap” (entrenched patterns of daily verbal communication) in oral development during SA, with important implications for heritage language education, multilingual learner support and SA programme design.