Does the American English exist ?

Hello every body, let's talk about some cultural facts !!

A famous writer said that Britain and America were divided by the same language.
Even today, hundreds of books and articles pour into the market, affirming or denying the existance of a true american language.

Some say that the differences between British and American language are lexical only, while others insist that in hundred years time, British and American will need an interpreter to understand each other.
So, what is the truth behind this great debate? In fact, it is very difficult to be definitive.
Of course, thare many differences in word usage, and a british visitor can often have more difficulty to understand his American cousins that non-native English speakers (frenchies for example).
This funny example will show us the great rivalery between American and British :

An American was driving through New York with British friend when it started to rain.
US man : I can hardly see through the windshield (pare brise)
BR man : You mean the windscreen?
BR man : After all, we invented the language.
US man : I mean the windshield, after all we invented the automobile.

Aimane (hey man !)