Exploring the theme of communication, Auel assumes that the Neanderthals lack the full vocal development of modern humans and has the clan using a mixture of gestures and body language to supplement their small vocabulary. (abroadintheyard.com)
Rvachew, S, Creighton, D, Feldman, R. «Vocal Development of Infants With Very Low Birth Weight.» (verywellfamily.com)
Babies will respond to music by making their own sounds, advancing language and vocal development. (breastfeedbabywearclothdiaper.com)