The verbal diarrhoea and bizarre speech strong drugs (not necessarily Heroin) cause in bag heads and Chavs.
They slur, stammer, and speak from the back of the throat in a strange, zombie like, and above all LOUD voice, with entirely random emphasis, and a truly stunnin use of the word FUCK in all its forms, used where there should have been a pause. All apparently with absolutely NO self awareness AT ALL!
See Bez from The Happy Mondays for an excellent example!
Man, Im fuckin WELL in fuckin NEED man, fuck, you know what I fuckin MEAN man, lets DO this fuckin place man, come on, fuck it, I dont fuckin give a SHIT me man, you know what I fuckin MEAN man? FUCK! U got any spare CHANGE man? HEY!! FUCK you man FUCK you!! etc etc etc ad nauseum