In most countries you learn the official language at school and talk your local dialect at home/friends/shops so when you meet somebody from out of town you can still have a normal conversation. The Brits don't seem to have that system and want us all to understand their particular lingo. Same when they need to speak another language, they just talk their talk only louder.
BTW. I really would like to know the difference and correct use of, sleeping and asleep.