A great article on both the use and study of gestures through the ages.
While aspects of the way we do it are learned or culturally conditioned, and while some of our gestures are intentionally formed with the goal of communication in mind, imitation can’t explain why congenitally blind people gesture, especially when they know they’re speaking to other blind people, and communicative intent can’t explain why people gesture when they’re on the phone. Gesture is simply a part of language use. When we form our thoughts into speech, some of it leaks through our hands.
I particularly enjoyed the ancient advice on what gestures are appropriate to use during the introduction of a speech. It feels like I can see the orator at work, thousands of years in the past.