The Effects of Noise on Bilinguals' Memory During Language Tasks: A Systematic Review

This thesis aims to investigate the effects of noise on bilinguals’ memory performance during language-related tasks. Although substantial evidence indicates that noise disrupts speech perception and cognitive abilities, most of this research has focused on first-language (L1) listeners, with far less attention paid to the actual cognitive costs for bilinguals and second-language (L2) learners. Through a systematic review and the analysis of six experimental studies, the effects of speech noise and non-speech noise on working memory and recognition memory were investigated. The findings show that noise consistently reduces recognition memory performance, with greater declines in L2 compared to L1, while its effects on working memory depended on task type and acoustic configuration. Furthermore, L1–L2 differences persist even in the presence of speaker familiarity interventions or the use of noise-reduction technologies. Some studies suggested that multi-talker speech noise caused greater disruption, particularly in tasks involving phonological processing and serial order retention. This pattern can be explained within the frameworks of Cognitive Load Theory (CLT), the Ease of Language Understanding (ELU) model, and the Framework for Understanding Effortful Listening (FUEL), all of which highlight limited processing capacity and increased executive demands under adverse listening conditions. The study underscores the need to reconsider the design of educational and professional environments in order to reduce auditory–cognitive inequalities between bilinguals and monolinguals.