Hi Filipe, I am teaching a British English Method now and there is little difference between American English & British English. The pronounciation is different of course and some vocab. ie Pants/Jeans (American English) are called Trousers in British English. A cap is a hat and other than that it will vary mostly is in Slang & Idioms. I agree with the comments, if you learn one you can be understood anywhere.. I would suggest you learn with a teacher from the country that you are most interested in visiting one day.

There is only one English language. It is spoken my many different nations. The accents are all a little different and some words are more commun in one country than another. But basically they all the same. There are also some small differences in spelling but nothing that causes a problem.

So I'll start with the British, since there are more resources available on the Internet. Thanks guys.

If you learn one, everyone can understand.

I think it's the same thing man, maybe the accent and a few words/expressions, but everything else is the same.