What we call cockney speech today, in its backbone, was the speech of the citizens of London. Not necessarily the lower-order, citizens of all classes, except probably the Court. In certainly the late Middle-Ages and certainly in Elizabethan times.

In Queen Elizabeth’s reign, a London funeral director, Henry Maichin, kept a diary. The spelling mistakes in Maichin’s diary are vital clues to the sound of Elizabethan London English. When Maichin wrote “alff a hundred in red and wyht” this is the spellin of the word “half”. Describing a mugging: “a man frust be-tweyn the rybes” this is the spelling of “thrust”. Henry Maichin dropped “h”s off his words because he hardly ever heard the “h”s sounded. He wrote words like chains and strange with a “y” in them instead of an “a”. He actually wrote them as chynns and strynge because he heard people say them like that.

What you see in these is the representation of the way people spoke. He wrote words lie “mother and “feather” as “mover” and “fever” with “v’s” in them. And you know there were so many more of these. Up to the 18^th century, up to say about 1750.

Cockney was the speech of anybody and everybody in the city of London. But the second half of the 18^th century was an age of great social change. Because it was an age of change you had a new social class who wanted a way to identify themselves.
The way they picked on was speech. If you spoke properly, if you had good grammar, pronounced words in a received way, then you marked yourself as a member of the upper-class. And so Cockney, the speech, which had been the honourable speech of the citizens of London, in a quite short space of time, became the speech of the lower orders who lived in the Dockside districts of East London.

Now Cockney was treated, not as another variety of English like Scots or Yorkshire, but as bad, inferior, slovenly.