[[http://www.sciencemag.org/news/2016/03/how-sliced-meat-drove-human-evolution It seems that meat-eating by early hominins, and in particular, eating meat they'd sliced up using stone tools]], is one of the main features that allowed our brains, our skulls, and our jaws to develop the ability to talk. Pounding tough vegetationto eat, e.g. fibrous roots, also helped.