Didactic adjustments in fathers' and mothers' speech to their 3-month-old infants

Vocal dialogues of 3-month-old infants with their mothers and fathers were recorded during dyadic interactions in the laboratory. Six-minute speech samples were analyzed for syntacticlexical and temporal-melodic features. Both parents adopted strikingly similar speech registers. Segmentation, reduction in syntactic complexity, repetitiveness, and slow tempo were more marked than reported for parental speech to children above 1 year. However, rather than providing proper linguistic models, parents utilized simplified patterns of expressive melodic contours as the most salient units of speech. This tendency is interpretable as age-specific adjustment to infants' integrative capacities. Structural similarities between maternal and paternal baby talk by far outweighed a few quantitative differences. The intuitive nature of recourse to basic nonverbal properties of vocal communication, together with universality across sex, favors the assumption that baby talk is a part of species-specific didactic support to infant communicative development.