Hands: so useful, yet so problematic! What to do with them? Shove them into pockets? Use them to clutch the sides of the lectern with last-lifeboat-off-the-Titanic fervor? Flick away invisible flies?

When people talk face to face, they don’t rely on words alone. They move their hands, raise their eyebrows, or nod to help express what they mean. These gestures often carry meaning and help listeners ...