The chat bar appears near the bottom of the screen, and is used to enable a PC to speak outside a pre-scripted conversation. (Text entered into the this bar will be spoken by the PC.) Even though some NPCs will respond to such speaking, this is not the norm. The vast majority of the time, the chat bar is used to communicate with other PCs. If a player's character is dead, the chat bar is only accessible via the keyboard (the "enter" key), and only if the death options panel is currently visible.