Multilingual advantage or interference? a mixed-methods analysis of multilingual students’ English pronunciation in Thailand

Research on English pronunciation has largely centred on bilingual learners, leaving the pronunciation competence of multilingual learners underexamined, especially in EFL contexts such as Thailand. This study therefore investigated English pronunciation accuracy, factors affecting that accuracy, and the role of multilingualism in pronunciation acquisition among multilingual students in Thailand. Ten students completed a pronunciation test using the Speakometer app. The scores were analyzed descriptively to identify overall accuracy and phoneme-specific difficulties. Participants also responded to open-ended questionnaire items. The qualitative data were analyzed thematically to examine perceived influences on pronunciation learning. The quantitative findings indicated that the students generally produced segmental sounds accurately; however, they continued to struggle with the /ʒ/ sound in ‘genre’ and the /θ/ sound in ‘through’. The qualitative findings identified cross-linguistic transfer and interference, confidence, the social environment, and practice and media exposure as key factors affecting pronunciation accuracy. Multilingualism emerged as both a resource and a constraint, supporting phonological awareness and articulatory adaptability while also contributing to interference, overgeneralisation, cognitive overload, and reduced confidence. The study offers pedagogical implications for pronunciation teaching in multilingual EFL settings.