the one you speak every day.

Josep hit the nail on the head, but you don't think about your own language when you speak your mother's tongue. I don't, do you? Somebody else's tongue gets interesting. "Of course" tells the story of how English came through the gauntlet to become the international these days. In a generation another language could depose the king, long live English. I have taught English to Swiss bankers, CEO's, commercial airline pilots, military people, VIP's, film stars, sports stars, medical people, computer people, it's all being done in English these days. In South America a secretary who speaks English has a bigger salary than a lawyer, money usually makes things more important, in my opinion. Good Q!

every lanuage is important , you learn the lanuage for some aims like communication , job or interested in that culuter and so on , but what i notice that english becomes so important nowadays but that wonot be last . at all my lanuage arebic is so important.

English !!!

Of course, it is the language that you use everyday. English, I guess is secondary, but important though since its commonly used, like medium for teaching in most schools (well, in my country), used for business. Hence, an international language. But nothing is more comfortable than speaking your very own language.