Plenty of studies have shown how language positively impacts learning. Now, a new Swedish study using magnetic resonance imaging (MRI) shows that learning a language actually increases the size of the brain.

Researchers worked with ideal subjects — new recruits to the Swedish Armed Forces Interpreter Academy. At the beginning of the study, the young men and women had no prior knowledge of the languages they were about to learn, whether Arabic, Russian or Dari, which is spoken in Afghanistan. After 13 months of intensive daily lessons, those recruits could speak their respective languages fluently. After three months, researchers observed the recruits’ brains through MRI as well as another group of hard working learners — medicine and cognitive science students at Umeå University who studied just as often, but not languages.

Although both groups worked every day to understand their subjects, the brains of those learning a language actually changed while the others’ remained the same. Specific parts of their brain, like the hippocampus and areas of the cerebral cortex, had grown during that time. In fact, those who were better able to comprehend a language had more growth in their hippocampus and areas in the cerebral cortex related to language. Learners who found that languages were more difficult for them still saw growth, but in the motor region of the cerebral cortex.

Researchers mused that their findings may have something to do with why bilingual or multilingual groups develop Alzheimer’s disease later in life than those who only know one language.