A light-hearted look at English as spoken by Londoners (Cockneys)
Cockney rhyming slang has uncertain roots. It is said that it was once spoken by the thieves of London. It would certainly have been a very effective code, being incomprehensible to the authorities or any eavesdroppers who were not familiar with the slang. There is little evidence, however, to suggest that it was particularly widespread.
The problem in researching its origins is that it was largely a spoken language with very few written records. What is more, if it was a secret code used by traders, entertainers, and thieves, then the secret has been well kept. We will never be certain how widespread its usage once may have been.
The Cockneys were – and for the mostpart still are – working class Londoners. The word comes from cockeneyes (14th century) which means eggs that are misshapen, as if laid by a cock. The word went through a series of usages over the centuries, and it came to be used to refer to city folk, ignorant of 'real life'.
Nowadays the definition of Cockney is often one which originated during the 17th century. It refers to anyone born within the sound of Bow-bells. These are the bells in the tower of St. Mary-le-Bow, commonly but in fact erroneously called Big Ben (Big Ben is not the tower, but the largest of its bells). The term is still usually used in a somewhat derogatory sense.