It does take years. The brain is very pliable and easy to teach the younger you are so it depends on when you start. I'm not much of a polyglot myself: English

It does take years. The brain is very pliable and easy to teach the younger you are so it depends on when you start. I'm not much of a polyglot myself: English, French, Swiss-German, Afrikaans (mainly the insults!) but my sister can speak 8 languages fluently (she's a professional translator) and the basis of my comment is on her observations of language.