Wonderful, do you know any other significant differences between these two?
:-) I think, Irina was talking about somewhat different things (i.e. particularities of spoken versions of the languages or something like that).
To my mind, one of the main differences is that American English (I consider its GA version as the most recognised one) is "rhotic", whilst British (in its RP-version) is "non-rhotic" - it means that Americans usually pronounce the letter "R" in all positions, including the ones before consonants or at the end of words), while RP-speakers pronounce it only before vowels.
There are also a lot of differences in vocabulary (some of them are slight and can sometimes be neglected, others are much more significant).
Just compare "pants" and "trousers" or the way the word "car"is pronounced etc..
Of course, the complete list of those differences has not been made in this message :-)))
Regards, Vladimir