It’s not just (just in case definition) being able to crack a joke to the locals or order off a menu without being served something disgusting, learning another language has some surprising benefits for your brain.
Specific brain areas increase in size and function, including Broca’s area, which is usually in the left hemisphere and involved in language production. When children grow up bilingual, both languages are processed in the same area. Yet when adults learn a second language, a separate area develops close to the first.
Some adults learn more quickly than others and one study showed differences in the brain areas that changed: the hippocampus and Broca’s area altered most in the fast learners and the motor cortex in slower students. Some effects depend on the person’s first language. For example, native Japanese speakers cannot readily distinguish ‘r’ and ‘l’ when learning English because in their brains both these sounds activate the same area. In native English speakers, however, the sounds activate distinct areas.
More generally, learning a new language improves brain function, providing better memory, more mental flexibility and creativity, and can even delay the onset of dementia.