I'm no fan of Palin's, but the little I've read about linguistics suggests, counter-intuitively, that the coherence and diagramability of her speech aren't reliable indicators of her intelligence or clarity of thought. Chomsky's notion that language isn't the product of some sort of general intelligence, but of a specific module in the brain, is generally accepted today. If the module works, speech is automatically grammatical, even if the person in question is mentally handicapped. Conversely, if the module is broken, an otherwise capable person can't produce coherent speech. Thus the stroke victim who can carry out all sorts of recognizably intelligent tasks, but can't speak grammatically. Grammar here doesn't refer to the rules of standard written English, but to the rules underlying all coherent speech in any language - the so-called Universal Grammar. Apparently it's fairly difficult to depart from these rules. The reason most of us don't utter mangled Bush-style howlers isn't because we're smarter, but because it would be seriously difficult to do so. Just how smart or dumb Bush is, is another question.