differences in spelling, sounds, grammar etc.
American English has grown steadily in international significance since World War II, parallel to the growth of U.S. political, economic, technological and cultural influence worldwide. American English is currently the dominant influence on "world English" (cf. British English) largely due to the following:
International political and economic position of the U.S. (cf. Kennedy)
There are many English words which are different to American words.
Lisa and Sofia Efthymiou, an American mum and daughter, have listed below a few of the differences between British and American words.