Mind Your Language: Thought, Metaphor and Imagination

Language ranks among the most powerful influences on human existence. Even so, language presents many mysteries that are the subject of heated debate. Was there a rewiring of the human brain which gave us the capacity for language? Or is it a human invention developed to facilitate group cooperation? Is language primarily a communication tool or the substrate of inner thought? And how is it that with a few choice phrases language can fire the imagination or transport us to the stars?