The American English and the British English have several differences.
The most obvious one is they have differences on the pronounciation.For example,the word "car".In the American English,it is called [kar]; but in the British English,it is called [ka:].
Another obvious one is they have some differences on the spellings.For instance,the word "colour" in British English has the same meaning with"color"in the American English.
Besides,they also have some differences on the expressions.This one don't easy to be find.
All in all,these two are similar to each other,and exist the differences also.