From crying to words: Unique or multilevel selective pressures?

In the first year of life, infants' utterances change from high-intensity crying to low-intensity acoustic sound strings, acoustically labelling the first word. This transition implies: (1) decoding of phonetic sounds, (2) encoding of phonetic sounds, and (3) a unique linking of an articulated sound to a specific object. Comparative, ontogenetic, and phylogenetic aspects are considered for multilevel selective pressures. © 2006 Cambridge University Press