Cross-Linguistic Perspectives on Aging and Sentence Processing: The Role of Word Order and Semantic Plausibility

This cross-linguistic study investigates how healthy aging affects sentence comprehension across three typologically distinct languages-English (head-initial), Korean, and Japanese (both head-final). It explores how syntactic word order and semantic plausibility interact with aging and whether these effects differ across languages with varying structural characteristics.

A total of 290 adults participated: 103 English speakers (49 younger, 54 older), 98 Korean speakers (50 younger, 48 older), and 89 Japanese speakers (43 younger, 46 older). All participants completed a sentence-picture matching task using auditorily presented stimuli. The sentences were systematically manipulated for semantic plausibility (plausible vs. less plausible) and word order, contrasting instrument-first (instrument-theme) and theme-first (theme-instrument) structures.

Aging effects were observed across all languages, with older adults performing worse than younger adults. Across language groups, participants showed better performance for instrument-first sentences than for theme-first sentences. Semantic plausibility interacted significantly with age across all languages in both accuracy and response times, indicating that older adults were disproportionately affected by reduced plausibility. In contrast, word order effects were largely similar across age groups, although a significant Age Group × Word Order interaction was observed in response times for the Japanese participants only.

This study demonstrates that systematic manipulations of simple sentence structures can effectively expose age-related and cross-linguistic differences in sentence processing. The findings illuminate both universal patterns of cognitive aging and language-specific parsing mechanisms, informing the design of sensitive and typologically flexible tools for assessing cognitive-linguistic decline.