Working Memory and Semantic Processing of Sino-Korean Words in Korean-Japanese Bilingual Older Adults

Objectives: This study aimed to examine whether lifelong bilingual experience contributes to cognitive reserve in older adults. It focused on differences in working memory and semantic processing abilities between Korean-Japanese bilinguals and Korean monolinguals, considering the influence of typological similarity between the two languages. Methods: Thirty older adults (15 Korean-Japanese bilinguals, 15 Korean monolinguals), all native Korean speakers over 60 years of age, participated in the study. Working memory was assessed using digit span forward and backward tasks. Semantic processing was measured through a semantic relatedness judgment task (SRT), which consisted of word pairs constructed from Sino-Korean words. Stimuli were shown in two formats: Hangul script only, and mixed Hangul-Hanja script. Each pair was either semantically related or unrelated. Participants judged whether the two words were meaningfully related and their accuracy and response times were recorded. Results: Bilingual participants outperformed monolinguals in both working memory tasks. In the SRT, they also showed higher accuracy and faster responses across all conditions. While both groups experienced more difficulty with mixedscript and semantically unrelated pairs, bilinguals consistently demonstrated better performance. Conclusion: The findings suggest that bilingualism involving structurally and lexically similar languages, such as Korean and Japanese, may enhance cognitive reserve and facilitate more efficient language processing in aging. This highlights the cognitive benefits of bilingual experience and its relevance in the context of age-related cognitive decline.