Physical brain size has been found to increase in adults who learn a new language. The structure of the brain remains the same, but certain parts might increase in size after an in-depth language study, research has shown. The main change typically is to the hippocampus, the structure that is responsible for memory, particularly converting information from short-term memory to long-term memory. Other parts of the cerebral cortex, the brain's outer layer that is often called gray matter, might be affected, depending on how much effort a person has to put into learning a new language. A Swedish study found that people who learned a new language more easily had larger growth in the superior temporal gyrus, which is related to language learning. Those who struggled were more likely to experience growth of the middle frontal gyrus, which is related to motor function.
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