APA Dictionary of Psychology

development of the earliest forms of perceptual experience, learning, and communication, which precedes actual speech and is necessary for its development. For example, babies attend to sound at birth and can differentiate the human voice from other sounds within the 1st month. Cross-cultural studies reveal that mothers routinely use techniques that help their infants acquire language; for example, they shorten their expressions, stress important words, simplify syntax, and speak in a higher register and with exaggerated distinctness. See babbling; infant-directed speech; infantile speech.