In the 13th century, Frederick II was the Holy Roman Emperor. He supposedly carried out a famous language deprivation experiment where he had infants raised by foster mothers who were not allowed to talk to them--they could only feed and bathe then. This was to see if there is a natural human language, he thought Greek or Hebrew might emerge. It turns out that the children all died. In sociology this is taught as proof that humans need language and social interaction to survive. But the whole story comes from a single Franciscan monk who was apparently not a fan of the emperor, so there's some doubt.