If you have watched the movie Lock, Stock and Two Smoking Barrels, you may have had a taste of the Cockney language.
Cockney was born in Eastern London and is referred to as rhyming slang. It developed among the working class. Some reasons for the creation of the cockney language are believe to be for criminals to confuse the police and maybe to use in the marketplace so vendors can talk without customers knowing what was being said.
An example of this is "apples and pears" meaning "stairs" and the one in my blog title- "giraffe" means "laugh".
Here is a great website for reference.