Language dominance and lexical change in heritage Bai: A contact linguistics approach

Aims and objectives: This study investigates whether and how external factors, specifically language dominance, shape two types of lexical-level language change: word borrowing and vocabulary simplification in heritage Bai, as spoken by Bai–Chinese bilinguals in Dali, Yunnan, China. Design/methodology/approach: Data were collected from four Bai–Chinese bilingual speakers using storytelling and free-speech tasks to capture lexical change of Bai language. Language dominance was assessed via a questionnaire covering speakers’ language history, proficiency, use, and attitude. Data and analysis: Word borrowing was quantified by calculating the ratio of Chinese borrowed words in both tasks. Vocabulary simplification was measured using the Moving-Average Type-Token Ratio. Bootstrapped linear regression analyses were conducted to examine the relationship between language dominance variables and the two types of lexical change. Findings and conclusions: Regression results indicated that the combined dimensions of language use, proficiency, and attitude significantly predicted word borrowing, particularly in the free-speech task. However, none of the language dominance components significantly predicted vocabulary simplification. These findings tentatively suggest that although both phenomena occur at the lexical level, they may be governed by distinct mechanisms. While lexical borrowing appears closely tied to sociolinguistic dominance and external influence, vocabulary simplification may result from slower, internally driven processes. Originality: This study is one of the first empirical attempts to examine how specific sociolinguistic factors influence different types of lexical change in a bilingual context. The use of fine-grained language dominance measures and methodological design offers a novel contribution to future studies on language contact and language change. Significance/implications: The findings underscore the need for models of language change to consider both internal linguistic dynamics and external sociopsychological factors such as language dominance, particularly in bilingual setting.