I’ve always been fascinated by the use of slang language in books, film, and gaming. Thanks to the internet, it’s easy to find resources for these. For example:
1736 Canting Dictionary: Since 1st Edition, rogues (“thieves”) have had access to a special language called Thieves’ Cant. In case you were unaware, it’s the slang used by various brigands and hustlers of Elizabethan England, and shows up in such things as Jacobean Plays and various “rogue literature.” Here’s the website to translate the slang into ‘contemporary’ English, which happens to be from 1736. What can I say, I always wanted to run a game heavily using Book of Roguish Luck.
The Vulgar Tongue: For something slightly more recent, this is the copy of a British dictionary of underworld slang. More in-depth than the earlier Cant dictionary, and still very British, but still pretty interesting.
18th and 19th Century Thieves Cant: Here’s some more underworld jargon for the age of empire. Honestly, though, it just compiles the previous two into a more categorized database, with a few other additions.
Twists, Slug, and Roscoes: As you may have noticed, I’m big into pulp fiction. Not detective/crime fiction specifically, but it is the most prominent pulp fiction genre alive today. It has its own dictionary of slang terms and jargon going far beyond gun molls and house dicks, and while it’s not quite as dense or obtuse as Thieves’ Cant, it’s still pretty foreign. Here’s a dictionary to keep your head afloat while reading a lot of Hammett and Chandler, or to spice up your own noir adventure.
Guide to Jazz Era Slang: More slang from the ’20s and ’30s, era of prohibition, speakeasies, the lost generation, and (obviously) Jazz.
Gangster Slang: Much as it sounds, a big list of slang from the thugs and mugs.
Cyberslang: Slang used in Cyberpunk, dating from the 1980s and ’90s; given that cyberpunk itself relies heavily on the same tropes and themes as pulp noir, it makes sense that the underworld of the technological future has its own built-in lingo.
Shadowrun & Cyberpunk Slang Glossary: A MS Word .doc with more info than the last link, 14 pages in length. It’s pretty much the non-plus ultra of running/reading/writing in cyberpunk terms. It’s also on scribd if you don’t want to download anything.