I do believe that when someone learns another language, it is capable to see and understand the world from a different perspective. And it happens because that person learns a different approach to things, concepts change and, in a way, it has to learn also to think in that language so that person can be closer to the meaning is intending to transmit.
Everything comes from the simplest concept to the most sophisticated definition of the world. While some cultures may have one concept for a certain material thing, another culture may have different definitions for that same material thing, and it can be also applied for the abstract, like definitions or levels of love and hatred.
Of course this subject is very extended and I could put several examples of it, instead, I leave a link to an article that explains more about this subject. Based on this information and the fact that I am very passionate about linguistics, I think that learning several languages, and not even to be perfect in each language, but to have a general idea of each one, may be the key for a better communication and relation towards other people in the world, because if we can experience a glimpse of other cultures’s perspective, then we will be able to understand the figure of the ‘other’, judge less and respect each others differences, as you will be able to see that every language has its differences and similarities, and in scale, just as each culture and each individual person.
Thus, to speak several languages, might be one of the steps to live in harmony and balance with our surroundings.