Learning a second language not only allows you to communicate with the locals but also protects you from developing Alzheimer's disease (AD).

A study at York University (Toronto) revealed that bilingual patients were diagnosed with AD four to five years later than those who spoke only one language. 

The course of Alzheimer's disease is unique for every individual and learning a second language does not eliminate one's chances. However, after examining 450 patients - half of which bilingual - researchers concluded that (even elementary) knowledge of a second language may delay the appearance of AD symptoms.

Source: York University