Chat commands (unlike controls) can be typed into the chat in a room to make something happen. All commands start with /, and anything typed with / in front (even if it's not a valid command) will not be spoken in chat. If you wish to tell someone a command, you should place a . or other character in front of it (ex: ./mort). Unlike normal messages, chat commands can be entered into the chat again without modification without giving an error.
Change the language used by the game (doesn't affect messages already onscreen). Must be a valid 2-letter language code, or else the game the game while be stuck with a black semi-transparent overlay and unresponsive to mouse clicks. Ex: /langue es
Shows your current FPS at the top left of the screen. Enter command again to remove.
Shows the frame calculation time in the form of a graph. Enter command again to remove. Note that the image prevents you from clicking through it to access the chat, so simply click on the chat further to the right (or just hit ↵ Enter).
Toggles debugging on / off (currently doesn't do anything).
Lists out your current titles (currently none available).
Opens up a window to write the lua scripting language. Doesn't currently appear to do anything.
Opens the box for typing codes that give rewards (from contests, attending a convention they are at, etc).
You can monitor and vote on the innocence of a reported player. While the text says names show up in pink, they don't due to the red/blue team overrides.