Abstract

Bilingualism—the ability to use two or more languages in daily life—has been proposed as a protective factor against neurodegeneration and cognitive decline. However, existing findings remain mixed, often derived from small samples, and fail to account for key confounding variables such as migration status, socioeconomic disparities, and environmental factors.

In this talk, I will introduce a novel framework for examining bilingualism as a protective factor against cognitive, functional, and neural decline. This framework is based on computational aging clocks, which leverage machine learning models trained on large datasets to estimate normative aging trajectories across domains. The “age gap”—the difference between chronological and predicted age—captures deviations from typical aging, with negative gaps indicating delayed, healthy aging and positive gaps suggesting accelerated aging and increased risk of pathology.

I will present evidence showing that bilingualisms delays aging—reflected in lower age gaps across domains—thereby acting as a protective factor, while speaking only one language does not offer similar benefits. This effect remains robust even after controlling for key confounders. Finally, I will discuss the potential mechanisms driving protection, providing insights into how bilingualism promotes healthy aging and resilience across the lifespan.