A study published in the Annals of Neurology indicates that cognitive decline may slow down when people speak two or more languages — even if they learned their second language in adulthood.
While it’s been known for some time that speaking more than one language benefits cognitive function, across the lifespan, scientists could not conclusively determine whether people improve their cognitive functions through learning new languages or whether those with better baseline cognitive functions are more likely to become bilingual.
“Our study is the first to examine whether learning a second language impacts cognitive performance later in life while controlling for childhood intelligence,” said lead author Dr. Thomas Bak, of the Centre for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh, in a statement.
This study used data from the Lothian Birth Cohort 1936, comprised of 835 native English speakers who were born and living in the area of Edinburgh, Scotland. The participants were given an intelligence test in 1947 at age 11 years and retested in their early 70s, between 2008 and 2010. Two hundred and sixty two participants reported to be able to communicate in at least one language other than English. Of those, 195 learned the second language before age 18, and 65 learned thereafter.
Findings indicate that those who spoke two or more languages had significantly better cognitive abilities compared to what would be expected from their baseline. The strongest effects were seen in general intelligence and reading. The effects were present in those who acquired their second language early as well as late.
The Lothian Birth Cohort 1936 forms the Disconnected Mind project at the University of Edinburgh, funded by Age UK. The work was undertaken by The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology.
“These findings are of considerable practical relevance,” Bak said. “Millions of people around the world acquire their second language later in life. Our study shows that bilingualism, even when acquired in adulthood, may benefit the aging brain.”
The study is an important first step in understanding the impact of learning a second language and implications for the aging brain. It’s hoped this will result in future research on bilingualism and cognitive decline prevention, said Alvaro Pascual-Leone, M.D., Ph.D., an associate editor for Annals of Neurology and professor of neurology at Harvard Medical School.