Listen for laughter. The unicorn considered him with a large, purple, dubious eye; but when it spoke, it sounded on the verge of laughter. -- Pamela Dean, The Whim of the Dragon (2003) "The unicorn laughs," notes Yasmine Galenorn (Magical Meditations, 2003). Unicorn laughter is essentially a form of vocalized panting, with spasmodic bursts of air. Speech expert Evangel Machlin explains: The contractions which are both the cause and effect of laughter are identical with those of panting. The diaphragm contracts lightly, quickly, rhythmically, sending out puffs of breath which have the familiar 'huh-huh' sound. These puffs are nearly voiceless, and a great many can be produced between one inhalation and the next. They sound almost exactly like laughter. (Speech for the Stage, 1992) But just as an ability to distinguish between laughing and panting can be crucial in the course of human