Okay this is my West-Flanderish(from Belgium) slang.. Most Dutchtalking people don't even understand it. Which means at least we've got a real dialect. :D
Weed: weed/wiet, smoringe, pittinge, taffinge/paffinge, jar (as in jar jar binks), joint(French pronounciation), scheize(German for shit aka hash), hasjish
Speed: speed, witn, amphetamientjes, S
heroin: bruun'n, bruunzuger(translated brownsucker), shotteuse
E pills: pillen/piln, bollen/boln, mentn, spekn
MDMA: MD, kristallen
Cocaine: Coke, C, C-tjes
LSD: trips
mushrooms: paddels, paddo's, paddestoelen
ketamine: k, vitamine k, special k
GHB: liquide
I remember people called weed "stuff" when I was a preteen.
THE WOOD said:
also fortunately most drugs start with a different letter. we just simpy refer to them as a person and make up a name for it on the spot. For example "yo man get over here evan stopped by" means were about to do some ecstasy, or like "yo we need to hang out with kalvin too! havent seen him in a while," meaning we want some K with our E.
Whoa, that's some paranoid shit

The furthest we go, is when the dealer specifically requests it, saying "can you help" on the phone. The thing is, when you're vague like this, you don't know the details and when the dealer is a polydrug seller, it gets even more complicated.