What’s the deal with the Cookie Monster?

Sometimes, I wonder about the Cookie Monster.
Why does he talk that way?
And why is he obsessed with cookies?
I did a little research, and found out that he was a foreign exchange student, but the file didn’t say where he was from.
Only that he’d never left.
He keeps saying C is for Cookie, but his permanent record says he got caught sleeping with the home economics teacher in an attempt to get that upped to an A minus.
As for his English grades, there’s no amount of fur that blue furball could shag to keep from flunking.