Nowadays English is very non-uniform. Now it exists in tens dialects, among which most popular – British, American, Canadian, New Zealand and Australian. Four can be distinguished two which gained the greatest distribution today owing to political and cultural influence of their countries in the world – the British and American English from these.
British is an English basis, but even in the kingdom all talk on dialects: Irish, Welsh, Scottish. Closest to classical English language in which communicate in New Zealand, Australia and Ireland. These countries are rather isolated from the other countries. That is why, English didn't change – influence of languages and culture of other countries was limited on it.
What of them to learn? First of all, it depends on that, why in general English is necessary to you. But actually, the critical difference isn't present because all these versions of the same language, and between them is more than similarities, than differences. And still it is good to know differences to avoid misunderstanding.
We want to acquaint you with the main differences in the American and British English, without going into historical details.