Anne Karpf's delightful distillation of everything any physiologist, linguist, or shrink ever discovered about talking will make you even more self-conscious about your voice. (See chapter 8 of The Human Voice: ''Do I Really Sound Like That?'') Good news for the tongue-tied, though: She considers even primitive jabbering miraculous (''No moon-shot could demand greater precision''). While noting Ronald Reagan's ''feminine, expressive dimension,'' Karpf insinuates elections were lost on Al Gore's ''monotone,'' John Kerry's ''flat, stentorian'' style, and Howard Dean's ''raucous shriek.'' Maybe Democrats need to study chapter 6: ''Mothertalk: The Melody of Intimacy.''