Presents French-speaking researchers' contribution to differential developmental psychology. Traces methodological and theoretical transformations necessary for understanding individual differences within a general theory of cognitive development. Provides overview of pluralistic and multidimensional model of cognitive functioning/development…

Sampled the speech of American, French, and Swedish mothers to their one-year olds, to analyze distribution of phonetic parameters of adult speech, as well as children's own early words. Found that variability is greater in child words than in adult speech, and mother-child dyads showed no evidence of specific maternal influence on phonetics of…