This is really interesting. And i think that learning a new language helps you in all the different aspects. If you are mastering a foreign language, it will be good to help you as a tourist, talk with native speakers, for a new job or just to have fun. But to be interested learning a new language depends what is your native language. For exemplo, for us in Brazil, that speak portuguese, if we want to travel around the world, necessarly we have to learn a second language, as english or spanish. But if you are borned in UK for example, you already can travel around the world just with your native language. But naturaly that everything is a bit relative, because even if here in Brazil we speak portuguese and consequently we should learn a foreign language, but many times we don't learn. So much people in Brazil that don't speak a second language (even spanish that has some similarity with portuguese), in compare with the amount of inhabitants that we have here.