It has long been known that spoken and written language, as well as American Sign Language and the whistles that Canary Island shepherds use to communicate, are processed there, are processed in Broca's area and Wernicke's area (or inferior frontal gyrus and posterior temporal region, if you prefer), . It has just been discovered that non-verbal gestures are also processed there. This would include facial expressions, obscene hand gestures, shrugs, body language. This suggests the area may deal more generally with symbols, of which gestures and spoken and written words are examples.
I was aware of Baby Signs and other versions of the same thing, so I guess it should have been obvious to me, but it was new to me when James F. Battey, director of the NIDCD (National Institute on Deafness and Other Communication Disorders, one of the National Institutes of Health, which funded the study), said,
In babies, the ability to communicate through gestures precedes spoken language, and you can predict a child's language skills based on the repertoire of his or her gestures during those early months.It strikes me that this suggests an infant's gesture ability can be used as an early language screening tool.