What happens in your brain when you learn a second language? The hippocampus and cerebral cortex get larger. The grey matter in the brain becomes denser and the amount of white matter increases. These changes are most noticeable in children that learn a second language from a young age, but they are also visible in people who try to learn a second language as an adult.
It is theorized that humans developed language about 200,000 years ago. The evidence for this lies in cave paintings that show abstract and symbolic behavior that would only be possible if they had language. Another piece of proof is that the gene which allows us to move our facial muscles to make speech, FOXP2, differs from the gene which Neanderthals have. That means we must have developed language after we split from our common ancestor, which was about 200,000 years ago. The latest language could have evolved is 70,000 years ago because that is when humans started to spread across the globe, and they must have already had language for it to be the same in all humans.
We all start to pick up our first language when we are still in the uterus. Newborn babies cry with a melody and intonation that is specific to their language. They could only do this if they were listening from inside the uterus. Babies then learn by mimicking, practicing, and trial and error. As they pick up the language, different parts of their brain start to grow. Language is processed in three parts of the brain. The first part is Broca’s area, which is in the left hemisphere. Its job is to produce speech and articulate ideas. It starts to fire when we begin to speak, but fades as we continue speaking. It operates when we listen as well, but if it is a word we recognize, it fades quickly. If it is a word we don’t recognize, it fires for longer. The second area is Wernicke’s area, which is in the posterior superior temporal love. It is connected to Broca’s area and it is responsible for comprehension. The last area is the angular gyrus, which is near to the areas that process auditory, visual, and sensory signals. Its job is to connect words to images, sensations, and ideas.
When we learn a new language, these parts of the brain change, but they change in different ways depending on when we learn a language. If you learn a second language as a child, say you have parents of different nationalities, the two languages develop in the brain as though they were one language. The Broca’s area just becomes bigger than it would if they had only learned one language. However, their brains undergo changes that a speaker of one language doesn’t have. Their brains grow more neurons and dendrites, the connections between the neurons, which makes the grey matter part of their brains denser. It also has an effect on the white matter, the part of the brain that connects the different lobes. The white matter is strengthened, and their brain communicates between the lobes more effectively. More fibers grow and the white matter volume increases. They also have changes in their anterior cingulate cortex. This is the part of the brain responsible for attention allocation, decision making, ethics, and morality. In bilingual children, it becomes more dense because it is heavily involved in monitoring which language is being spoken and switching the language to be used in the brain.
When you learn a second language as an adult, there is a different process. The part of your brain that deals with your native language is already set and cannot be changed. The second language cannot be mixed in with it in the way it is with bilingual children. When adults start to learn a second language, most of the processing is done in the frontal lobes. As you practice more and become more fluent in the second language, the processing moves to the parts of the brain that are used to process your first language. However, unlike with children where they mix, in adults, a whole new area is built. You will have a second area in your Broca’s area that deals with the second language. However, you will still get the benefits of a denser grey matter and more white matter. Your brain will become better at processing and learning a second language has benefits that cross over into other parts of life. Second language speakers have increased concentration, better memories, and it can delay the onset of dementia by over four years. And this is what I learned today.
Sources
https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-017-0405-3
https://memory.ucsf.edu/symptoms/speech-language
https://www.discovermagazine.com/mind/how-learning-a-language-changes-your-brain
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5845836/
https://www.cambridge.org/elt/blog/2022/04/29/learning-language-changes-your-brain
https://dana.org/article/how-does-the-brain-learn-language
https://en.wikipedia.org/wiki/Anterior_cingulate_cortex
https://neurosciencecommunity.nature.com/posts/15138-learning-a-second-language-remodels-our-brains
https://resources.unbabel.com/blog/brain-language-learning
https://www.sciencefocus.com/the-human-body/what-happens-in-our-brain-when-we-learn-languages/