"Words That Work - it's not what you say it's what people hear" by Dr. Frank Luntz. Hyperion. ISBN 1-4013-0259-9
For an interesting take on language. New book; may not be in free libraries as yet.

And I just throw this into the mix : Ever had the situation where some esoteric thing was explained to you and you fully understood only later to be unable to explain it to someone else, even though you still understood it? Words fail. Sometimes. And then there is Ameican Sign Language (ASL)
But those are enough cats among the pigeons to be going on with.