The current speaking style favoured by London's urban yoof is heavily accented as well as typified by slang expressions. Hackney being an area of East London (in which I reside) which has the dubious honour of being the worst borough in Britain repeatedly. Please note that the slang described here is common throughout britian, and is an accent developed often by well spoken people to attain street cred.
The general Hackney Patois comes from a mash up of east london cockney, afro- carribbean, general chavspeak and Hip-Hop slang often attributed to British Asian yoof as popularised by Ali G.
The vocabulary is inextricably linked to cellular phone sms (text) messaging, and online instant messaging, where limited space and speed of texting required abbreviations (m8 - mate, l8r - later, etc.) So much that often the true spelling of words are forgotten. Predictive text messaging has reversed some language - e.g 'book' was used for 'cool' as that was easier to text is now being used in language.
The 'grime' music scene sees Hackney Patois at its core - see artists such as M.I.A and Lady Soverign
as overheard in Hackney patois....
"Put dat down - you iz not gonna get nuffin' "
"She luk at me like dat agen she gonna get sum licks, yea' "
" I dahn't wannit, its got peas in it, innit! "
" ya get me, bruv? "