New research reveals that bilingualism has a positive effect on cognition later in life. Findings show that individuals who speak two or more languages, even those who acquired the second language in adulthood, may slow down cognitive decline from aging. Bilingualism is thought to improve cognition and delay dementia in older adults. While prior research has investigated the impact of learning more than one language, ruling out “reverse causality” has proven difficult. The crucial question is whether people improve their cognitive functions through learning new languages or whether those with better baseline cognitive functions are more likely to become bilingual.