Language diversity and cognitive function: Exploring multilingualism across the adult lifespan

Epidemiological literature suggests that speaking multiple languages can delay onset for neurodegenerative conditions such as Alzheimer’s disease. Cognitive and neuroscientific explanations, however, remain inconclusive. While some studies have found behavioural and neural advantages of being multilingual (compared to monolingual) for working memory, inhibitory control, and attention across the lifespan, others have found no such evidence. An emerging focus on nuanced, dimensional measures of language experience as well as different outcomes depending on stimulus modality (visuospatial versus auditory processing) could potentially resolve these mixed findings. The current study examined correlations between continuously measured language experience and domain-specific cognitive functioning across visuospatial and auditory modalities. Participants ( n  = 90) aged 18–83 years completed the Language History Questionnaire v3 (LHQ-3), and visuospatial and auditory tasks indexing working memory, inhibitory control, and attention. Results indicated that language experience was not associated with performance across any cognitive measure for the younger or older adult group, apart from a positive relationship with visuospatial working memory accuracy for older adults. The findings add to the mixed literature and suggest that neuroprotective effects of multilingualism may stem from alternate mechanisms than cognitive reserve or practice effects. Examples of alternative mechanisms include increased resilience to neurodegeneration due to greater cerebrovascular activity and oxygenation in areas responsible for higher order cognition and language.