Directive language is either true or false.

Directive language such as "Close the door!" and "Don't move!" serves to attempt to get others to do as directed. As such it is neither true nor false. Informative language is either true or false, since it attempts to inform hearers of how the world is. If the world is as represented, then it is true. If the world is not as represented, then it is false. Directive language attempts to influence how the world is, and so can be neither true nor false.