Ontogeny, specifically the role of language in the human family now and in prehistory, is central to Locke & Bogin's (L&B's) thesis in a compelling way. The unique life-history stages of childhood and adolescence, however, must be interpreted not only against an exceptionally high quality human infancy but also in light of the evolution of co-constructed, emotionally based communication in ape, hominid, and human infancy.