I'm sure there would be some sort of [url=http://en.wikipedia.org/wiki/Thieves'_cant]Thieves' Cant[/url] or trade language in the inner city. There are plenty of historical examples of melting pots creating their own patois out of mixed cultures and languages. The Creole/Cajuns of the United States are a good example. 

Hell, even American English is a patois of sorts, given that it borrows so heavily from other languages. Much more so than UK English.