Narrator

Pressing (or  on Mac) toggles the narrator, a text-to-speech engine that automatically reads chat messages, including the username. This keyboard shortcut was intentionally hardcoded as to be unchangeable, but for unknown reasons, however, this stance appears to be under review. The narrator can be toggled between several settings: The narrator does not read commands or command outputs. Language of the narrator is defined in host system and cannot be changed from within the game (though, it can be forced by messing with Windows registry).
 * Off: The narrator is inactive.
 * All: The narrator reads chat and system messages.
 * Chat: The narrator reads only messages produced by players.
 * System: The narrator reads only messages produced by the system (command outputs, notifications, etc.).

The narrator can also be used in Singleplayer.