Assessing language dominance in bilingual phonetics research: The contribution of BLP indices

Aims and objectives/purpose/research questions: Research in bilingual phonetics and phonology often aims to identify factors that influence specific features of “accented” speech production and perception, with the goal of explaining patterns of cross-language influence. In recent years, language dominance has emerged as a key predictive factor in bilingual phonetics research, with tools like the Bilingual Language Profile (BLP) being used to assess it. Design/methodology/approach: This paper explores the concept of language dominance and reviews studies that highlight the versatility of the BLP as an assessment tool, particularly in relation to the phonetic properties of minoritized languages in contact with Spanish, as well as Spanish in contact with English. Data and analysis: The BLP is a widely used, open-source instrument that assesses language dominance through self-reports. It generates a continuous dominance score and provides a comprehensive bilingual profile, considering multiple factors such as age of acquisition, frequency and context of language use, proficiency in different language skills, and attitudes toward each language. Findings/conclusions: This overview demonstrates that: (1) BLP indices can quantify the degree of language dominance at the individual level, useful for participant screening, grouping, or as a predictor variable in statistical analyses. (2) Language dominance is best understood as a gradient, continuous construct. (3) Bilingual groups are inherently heterogeneous, with significant variation in language dominance, and the BLP can capture this heterogeneity in fine detail. (4) BLP indices can reveal asymmetrical language dominance effects resulting from language co-activation. (5) BLP indices may not always capture differences in bilingual speech production and perception. Originality: These findings highlight the explanatory power of the BLP indices in accounting for subtle cross-linguistic phonetic influences in bilingual speech production and perception. Significance/implications: This paper introduces key methodological and theoretical considerations for future bilingual phonetics and phonology research while also offering insights into the broader applications of the BLP for understanding bilingual speech.