English as native

The fact that there are some people with english as their native languages just blows my mind. It is their first language, they think on it, they know every single word, it is the only language they can most fully express their thoughts (well, unless they haven’t learnt another language). Wow, they can understand the most non-understandable sound of english speech! How is it possible? =) And what is more – they don’t actually have to learn another language: “Hey, I speak international language, so let’s speak english, like normal people?” For me it’s like a part of some fiction movie.