From the Wiki Page:
Degenerate Semantics is a role-playing game for 1-5 players and one Game Master (GM). The players will each portray a character who live in Emmaloopen's poverty-stricken lower city. They are young, wild, ambitious, and independent. This way of life is threatened by other factions, and the players will need to have their characters work together to survive and thrive.
In the process of playing the game, the players and GM will define and flesh out a language called Bandethal. A collection of street terms and slang, Bandethal is used both as a way to talk openly about illicit activities without alerting authorities and to establish street cred. The terms are liberally mixed in with plain English, or when the language is mature enough, can be used entirely on its own. The characters' success is in large part based on how proficiently the players wield the language.
User Note: a Game Chef 2014 finalist