Using Multiple Languages in Childhood Improves Memory and Prevents Brain Diseases

KAIST Research Results

Image showing the differences in whole-brain connectivity between multilingual children and monolingual children. Multilingual children exhibit stronger connectivity between the frontal lobe and the occipital lobe compared to monolingual children. Photo by KAIST

[Asia Economy Reporter Kim Bong-su] A study has found that children who speak multiple languages have better memory and improved whole-brain connectivity, which can help prevent degenerative brain diseases.

The research team led by Professor Yong Jeong from the Department of Bio and Brain Engineering at the Korea Advanced Institute of Science and Technology (KAIST), in collaboration with a team from Yale University in the United States, announced on the 10th that speaking foreign languages during childhood enhances cognitive abilities and brings changes to brain connectivity.

The team analyzed cognitive function scores and functional magnetic resonance imaging (fMRI) data of 9-10-year-old children in developmental stages using data from the Adolescent Brain Cognitive Development (ABCD) Study by the U.S. National Institutes of Health (NIH). The results showed that children who use languages other than their mother tongue scored higher on cognitive tasks measuring memory compared to children who only spoke their native language. Additionally, multilingualism was found to affect the whole-brain connectivity of the children.

The brain activates specific regions not only when performing tasks but also during rest. Functional magnetic resonance imaging (fMRI) allows observation of these activated regions and calculation of functional brain connectivity, which shows how these regions are interconnected.

The whole-brain functional connectivity (connectome), representing the connection patterns among all brain regions, varies from person to person and is known to reflect unique characteristics such as age, intelligence, and cognitive function. This has recently become an active area of research in neuroscience.

The research team focused on whole-brain connectivity rather than specific brain regions and observed that children who speak multiple languages have different whole-brain connectivity patterns compared to those who speak only one language. When performing memory-related tasks, multilingual children showed stronger connectivity between the occipital lobe and subcortical areas than monolingual children. Differences between the two groups were also observed during resting state when children were not performing any tasks; multilingual children exhibited stronger connectivity between the occipital lobe and prefrontal cortex.

Furthermore, using machine learning, the team successfully predicted whether a child spoke multiple languages or a single language based solely on whole-brain connectivity patterns observed during memory tasks and resting state. They were also able to predict the scores that multilingual children would achieve on memory-related tasks based on the memory-related connectivity patterns observed. This phenomenon was not found in monolingual children, suggesting that the whole-brain connectivity of multilingual children is more closely related to their behavior.

The research confirmed that multilingualism in 9-10-year-old children in developmental stages induces changes in whole-brain connectivity. Based on this study, it is expected to help understand how the effects of multilingualism evolve through developmental stages into adulthood. Moreover, multilingualism is anticipated to contribute to cognitive reserve that defends against cognitive decline associated with degenerative brain diseases such as Alzheimer's, aiding research into this phenomenon.

First author Younghye Kwon, a doctoral candidate, said, "We confirmed that the use of multiple languages affects cognitive function and brain connectivity patterns even in 9-10-year-old children, who have a shorter language usage period than adults," adding, "We hope this understanding of how these differences formed early in life take shape over time and continue to influence individuals into adulthood and old age will be helpful."

The study results were published in the November issue (Vol. 118, No. 49) of the international journal Proceedings of the National Academy of Sciences (PNAS).

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