Part of getting into character for this game is "learning you to speak proper English, innit". Its part of the roleplaying experience!
British players and GMs likely won't need this handy lexicon, as its the language of a Friday night on the town. Americans will likely know a lot of the words here, as British teenagers learn most of what they know from American TV anyway.
This section's pretty much for the rest of the world...
Words That Scum Use
Boozing - Going out to drink alcohol. Also "going on the piss", "getting pissed", "getting bladdered".
Fick - "Thick", i.e. stupid. It's worth noting that generally Scum will pronounce "th-" as "f-" or "d-", for example. Tracy: "where de fings dat dey wanted?" Cheryl: "froo dere.". We don't go overboard with this sort of speech style in the game system though, as frankly it'd make for bad reading and makes the Scum look like w40K orks.
F**ked up - Either "very weird" or "the victim of a physical assault" or "damaged." Surprisingly, not used in any way with regards to sex. Usage: "That tramp's hair was well f**ked up, so we f**ked him up, but I got blood on my jeans and now they're all f**ked up."
GTI - Any fast small car, regardless of whether its actually a Golf GTI or not.
Innit - "Is it not?" Normally appended on the end of a sentence, more as punctuation than as an actual question. Usage: "We're going down the pub, innit."
Mate - Halfway between an acquaintance and a friend, normally of the same gender as yourself. Usage: "You're a mate, mate." "We're mates, ain't we?" "Me and my mates going boozing."
Minging - Ugly, the opposite of shaggable.
On the Rag - Menstruating. Also sometimes euphemistically (though more old fashionedly) referred to as "Liverpool playing at Home", in reference to the red football shirt of the Liverpool team. Usage: "She's on the rag mate, I'm not shagging that."
Pissed - Drunk. Getting pissed, for example, is getting drunk - a major goal of any night out for the Scum. Note that the American usage of pissed (angry) is replaced with "pissed off", but this means annoyed rather than enraged. Conversely "going for a piss" is urinating.
Pisshead - Someone who drinks a lot of alcohol. Amongst Scum, this is a mark of respect rather than a derogatory term.
Preggers - Pregnant. Also "knocked up", "up the duff", "bun in the oven", "preggo", "PG", "in the pudding club", and many more. You know how Eskimos have hundreds of words for snow, because snow is such a common thing for them? Well, for Scum there are hundreds of words for pregnancy...
Pub - Public house, a place where alcohol is sold and can be consumed on the premises. Not quirky quaint olde english places, as America might associate with the word, but rather buildings with crumbling plaster, a permanent smell of urine and no food served apart from bags of scratchings. Usage: "Going down the pub. Coming?"
Scag - Heroin.
Scratchings - Deep fried pork skin, sold in little packets. A main food staple for Scum.
Shag - To have sex with. Not said in a camp Austin Powers accent, but still the question "wanna shag?" is perfectly acceptable Scum parlance. Other words for having sex include "bone" (male use only), "have", "screw" and of course the universally acceptable "f**k".
Shaggable - Sexually attractive. Also, "fit", "well nice", "totty" and "f**kable".
Rozzer - Policeman. "The rozzers" = police generally. Also known as "the filth", "the pigs", "them Nazis" and heralded by "I smell bacon".
Souped-Up - Enhanced, specifically relating to cars or car engines. Note that we're not talking F1 fine tuning here, but rather things like glowing blue underlights, unnecessary spoilers, excessive decals and deliberate holes in the exhaust pipes for that turbo-roar noise. Expert mechanics, these guys ain't.
Well - "Very". For example, well shaggable = very shaggable, well hard = very hard, well difficult = very difficult.
Words That Are Used at Scum
ASBO - Anti social behaioural order - sort of halfway between a warning and a conviction. Almost every Scum will have at least one of these, and people will often call the scum themselves "asbo kids".
Bad Children - What foreign shopkeepers like Mr. Patel call the Scum. Usage: "You are very bad children, you will be leaving my shop now."
Chav - What "normal kids" call the protagonists of this game, usually with laughter and contempt. Usually its people under the age of 25 who'll use the word "chav". A number of more local euphemisms may exist as well, like "ratboys" and "weasels".
Nicked - Arrested. Used by the police ("you're nicked, sonny boy") and sometimes by the Scum themselves ("you hear Darryl got nicked?")
Scum - What "right thinking decent people" call the protagonists of this game, usually with a spitting snarl. Usually its people over the age of 25 who will use this term.