American English suffers "colonial lag", meaning that the English that is spoken in America has roots in the 17th century and then diverged. British English evolved in ways that American English did not. \n\nThere's sentence structures Americans use that British do not. Like "have gotten", that "en" ending with "have" is an old form of English.\n\nYou'll see that in the French of Montreal, Quebeq, Canada too. \n\nI see it in my mother's Japanese, it's very pre WWII and she taught me "old fashioned" Japanese that make modern Japanese people laugh. "You sound like my grandmother." They would say. Hey! I was taught by a grandmother. \n\nIreland has colonial lag too. If you read Shakespear with an Irish accent the rhymes would work. \n\nIn England there's a class system. So one's station in life can be deduced by the accent one has. Changing one's class is more difficult because one's accent would show where someone came from. I think that's why there are so many different accents in England and smaller pockets of the population that speak them. There's history behind it. \n\nAmericans don't have a class system like that. There's a lot of movement up and down the social ladder caused by wealth or the loss of wealth. I think that national TV is blurring the lines of the accents in America. There are classes on how to loose a regional accent when going into business. What is the dominant accent... watch the TV News. The "Walter Cronkite" accent.  \n\nThe slang in England and America will be different and that's the most difficult thing for a non-native speaker to learn. You would not call a small pack worn with a belt around your waist a "fanny pack" in England. That's very naughty. It's not naughty in America. Americans don't call a cigarette a "f a g". That comes from "faggot" which lit the fuse on cannons. In America it means a homosexual. \n\nBritish speakers of English have difficult with the slang in Australia. Australians with Americans. We all share English but after the colonies were established the English evolved in different directions. \n\nThe main difference between British and American use of English will be seen with the vowels. I'd focus on that if I were you.  Speakers of British English don't open their mouths as wide as Americans. Reading their lips is a little more difficult.\n\nIf you have a DVD player, get a movie that is made in English, put on the English Captions, listen to the movie and look at how the words are spelled out. That's the cheapest way to learn a language. To witness it in action, in a situation, because language is more than the words, it's gestures, eye contact, how close you stand to someone when speaking.\n\nJust look at the French when they shrug their shoulders. Both shoulders are used, their hands go up, they pucker their lips, tilt their head. It's a full body "I don't know" motion. What you hear may be just a "pffft" sound. \n\nSo watching movies will help in the non-verbal communication. \n\nYou're going to be using a different side of your head reading English. Chinese characters come in the brain like art, sounds of birds, that sort of thing because they are pictures that have meaning. Alphabets that make words that are used in sentences use the other side of the brain, where math is processed. \n\nYou got your work cut out for you. Good luck.