Allows the user to set the language used by zone and group chat. Anyone that does not have the language skill you are using will see "<your name> says something in <Language_Name> that you don't understand".

The Language_Name must be spelled and capitalized exactly as it appears in the Languages list of your Skills UI window.

/set_language Language_Name

Can also be set via the UI by right clicking on a chat box, and picking the "Set language" option.