These differences are associated with functional characteristics—such as temperament, learning style, and motivation—and from status characteristics—including gender, race, ethnicity, and social class (Gordon and Shipman, 1979).
Children come to preschool with a set of cognitive skills and proficiencies that include language and literacy, reasoning, and general knowledge (Kagan et al., 1995). Although virtually all preschool children by age 3 or so have mastered the basic grammar and phonology and a reasonably large vocabulary for everyday learning and play, there are nevertheless large individual differences in areas that are related to achievement in formal learning settings. They vary widely in their language acquisition and use, their language comprehension, their understanding of number and causation, and their knowledge about the world around them. We review findings in the area of language and literacy, where much research has been done, and in mathematics, where a smaller but growing body of research is available.
A major source of variation among children is their rate of language development, a difference that begins in the early months of life. Roe (1974) found that, among 28 infants, the earlier a high rate of babbling occurred, the earlier every subsequent index of language maturity was likely to occur. Some researchers have found a pattern of gender difference in language learning, with girls more advanced in vocabulary learning than boys (Huttenlocher et al., 1991).
Although research has shown the developmental sequence of language learning to be much the same for all children, great variation in the rate of language learning occurs across as well as within languages. Each language has its own areas of complexity and irregularity, leading to slow acquisition, and its own areas of relative ease. Slobin (1985) tested children ages 2 to 4 who were learning one of four languages: English, Italian, Serbo-Croatian,