Why do we learn English language?

Why do we learn the English language?It is necessary to learn foreign languages.I learn English because I want to read foreign literature in the original.I understand that I must learn English.In short, I understand that I have to learn English in a proper way and I try to do it.That’s why pupils have got such subject as a foreign language at school.Everybody knows his own language, but it is useful to know foreign languages.English is used not only in England, but also in other countries.I know and like such English and American writers as Charles Dickens, Mark Twain and others.But it is difficult to visit countries, when you don’t know the language of these countries.