you speak XXXXX? you doing XXX? 这种句子一般是和你比较熟悉的人用的。For instance, instead of saying "are you alright?" to your friend, you may choose to say "you ok?" It really depends on who you are talking to. The main difference between American English and other types of English is the spelling of words. "Harbor" vs. "Harbour", "Center" vs. "Centre", and so on. In terms of sentence structures, British English and American English are mostly similar. A main problem amongst English students is the tendency to translate Chinese straight into English. As a result you may end up speaking or writing something that is grammatically correct, but in fact would appear strange to a native speaker. Similarly, you should not translate English word by word into Chinese either. A simple example: