How does learning a second language impact the brain and cognitive ability?

Introduction 

The globalization of the world has led to an increase in bilingualism and multilingual societies. This has resulted in more than half of the world's population actively learning or speaking a second language (Grosjean & Li, 2013).

The increase in bilingualism has led to an interest in the impact on the brain from learning a second language. Conventional wisdom has long taught that people who can speak multiple languages have advantages in cognitive ability and memory. With modern research, there is even more information on the specific impact learning a second language has on the brain, including the anatomical impact on the brain and the long-term benefits of language learning in general. 

Cognitive impact of learning a second language 

One of the major misconceptions of language learning is that in order to realize the cognitive benefits of language learning, you must learn a second language at a young age. Recent research, however, highlights that adult language learners experience the same cognitive benefits of children. 

When it comes to cognitive ability, people who speak multiple languages tend to be superior in the following categories.

• General intelligence 
• Memory 
• Decision-making 
• Focus and attention 
• Mental flexibility 
• Multi-tasking 

The reason bilingual individuals tend to be superior in these areas is due to “executive function”, which is what allows us to process information. Individuals who speak multiple languages generally process information across all of the languages in which they speak. This results in the brain being more active for longer periods of time, thus increasing executive function, allowing language learners to process a greater volume of information.

Bilingual individuals can identify sounds much quicker than monolingual individuals. This increase in sensory perception and auditory attention is one of the key factors that allows bilingual individuals to have a higher level of cognitive control.

The cognitive abilities are what bilingual individuals and the population at large can see on a day-to-day basis. The research is based on tests and studies that span decades, testing bilingual individuals against monolingual individuals across a broad spectrum of prompts and questions. The results are nearly universal that the ability to learn multiple languages produces positive cognitive abilities that are not dependent on social elements.

The cognitive benefits of language learning are the result of anatomical changes that take place in the brain as a result of language learning. This is one of the areas of language learning that until recently, has not been researched extensively. With modern technology, however, scientists are now able to identify how language learning impacts the actual structure of the brain. 

Anatomical changes in the brain from learning a second language 

Bilingual individuals share certain brain characteristics that researchers are now able to identify. The key areas of the brain impacted by learning a second language include: 

• Increased gray matter (GM) density 
• Increased cortical thickness 
• Enhanced white matter integrity 

The reason for these structural changes is increased neuroplasticity for bilinguals. This increase allows the brain of bilinguals to change structurally more easily. 

Increased gray matter density 

Gray matter in the brain is where most of the neuronal cell bodies are found. The regions of the brain involved in muscle control and sensory perception include gray matter. Bilingual individuals show increased gray matter density, which refers to changes in cell size of both neurons and glial cells, neurogenesis associated with both neurons and glial cells, and possible changes in the intracortical axonal architecture including synaptogenesis. 

Increased cortical thickness 

Cortical thickness refers to the thickness of the human cerebral cortex, which is a highly folded sheet of neurons. The thickness of the cortex is an important factor in determining normal brain development and is also a signal of possible neurodegenerative and psychiatric disorders. For bilingual individuals, studies and research has shown an increase in the thickness of the cerebral cortex. 

Enhanced white matter integrity 

White matter in the brain is made up of nerve fibers called axons. These fibers connect nerve cells, which allows brain cells to send and receive messages. Enhanced white matter integrity has proven to indicate better decision-making in old age. 

The anatomical changes of the brain seen in bilingual individuals have provided a deeper understanding of how and why these individuals show increase cognitive abilities. The underlying theme for bilingual brains is the increased neuroplasticity. This allows the brains of bilingual individuals to change and adapt at a faster rate than monolinguals.

There continues to be significant research into the brains of bilinguals and much more is sure to come to light in the years and decades to come. The research will continue to identify how learning a second language impacts the brain and the results of these changes. 

Impact of short-term language learning 

Most of the research being conducted regarding language learning is focused on long-term language experiences. This includes individuals that speak multiple languages daily, such as individuals that speak a different language at work, in the home and in the classroom. These cases represent long-term language experiences that last decades and perhaps lifetimes.

Research has also shown, however, that even short-term language experiences have an impact on cognitive abilities and the brain. In a study conducted in 2012, researchers looked at American college students studying Chinese vs. students not studying Chinese. The students were only learning Chinese as a hobby and for limited use, rather than for regular, prolonged use over a long time period. The students studying the second language showed greater executive functions in the brain and even more impressive is the executive control was tied to how much Chinese the students were learning.

The study, and other similar studies, indicate that even language learners that are only learning a language for a short-term or as a hobby still show signs of increased brain functionality. This research sheds further light on the impacts on the brain while language learning is taking place. It also provides further evidence that even at an advanced age, learning a second language can have a profound impact on the brain and cognitive abilities. 

Long-term benefits of language learning 

Research has proven that learning a second language improves memory. Thanks to long-term studies, learning a second language has shown that the improvement to memory is a lasting impact that carries over to old age, helping to protect against age-related decline and disease.

Bilingual individuals maintain cognitive reserve while fending off the natural decline of cognitive function that takes place at advanced ages. This allows bilingual individuals to stay sharp and maintain memories and executive control. 

Not only do bilingual individuals exhibit an ability to maintain cognitive reserve, but they also have shown the ability to protect against age-related illnesses, including Alzheimer’s. In one study, bilingual patients reported showing initial symptoms of Alzheimer’s at roughly 77.7 years of age. In the same study, monolingual patients showed initial symptoms at 72.6 years of age. The results of the study showed that bilingual patients showed initial signs of Alzheimer’s 5.1 years later than monolingual patients. 

The study also showed that bilingual patients with significantly higher degrees of atrophy in the brain were able to perform tasks at the same level as monolingual patients with less atrophy in the brain. This suggests that learning a second language can impact the resilience of the brain and allow it to stay sharp despite overuse.

Conclusion 

Learning a second language can improve cognitive abilities, provide short-term benefits in the brain and deter long-term age-related illnesses. These benefits are the result of alterations in the brain that have not been fully realized until recent research into the topic. 

For language learners, this means learning English or learning Spanish can have impacts that far outweigh the traditional day-to-day benefits that are often thought about. While much of the focus of language learning is on the improvements for travel, business or career development, the long-term benefits to the brain can provide a longer, happier life. 

As the world continues to become more connected, the need to speak multiple languages will continue to be more important. The result of these multilingual societies and people will be more cognitive control and more information into fighting age-related illnesses.