Yeah, I've certainly been surprised by accents down in Brick Lane and along Mile End when in London in the last years. Not least from a French-born friend of mine who has really taken on the accent since living in Hackney and various surrounding areas of East London. Re. 'nang', it reminds me of young London artists like Dizzee Rascal and also M.I.A. of Sri Lanken heritage. The latter had a big hit start of last year with 'Galang'; seems there are conflicting reports as to where this word may come from. It now means something like 'hot shit'. The accent certainly has a confident cowboy swagger to it (see fashion references too) to match the sparse rhythms of the London grime and dancehall scenes. An excerpt:

London Calling
Speak the Slang now
Boys say Wha-Gwan
Girls say Wha-What

Slam Galang galang galang
Shotgun get you down
Get down get down get down
Ge-d Ge-d Ge-d Down G-down G-down
Too late you down D-down D-down D-down
Ta na ta na ta na Ta na ta na ta

Blaze a blaze Galang a lang a lang lang
Purple Haze Galang a lang a lang lang
Blaze a blaze Galang a lang a lang lang
Purple Haze Galang a lang a lang lang