Developmental pathways of language development : a longitudinal predictive study from prelinguistic stage to outcome at school entry

Abstract

This research focused on the pathways of development during the prelinguistic stage and from prelinguistic development to later language ability. The first goal was to follow and describe the development of several prelinguistic communication skills during the first two years of life (Studies I and II). The second goal was to examine the predictive relations between this development and language ability and difficulties, as well as memory, up to school age (Studies I, II, and III). The third goal evaluated the feasibility of parental screening in identifying children at risk for language and communication difficulties (Studies I, II, and III). Prelinguistic skills were followed with a parental screener administered at three month intervals from age 6 to 24 months (seven measurements, n = 508, 203–330 by age). The same children were followed from ages 2 to 8 years (five measurements, n = 102–296). Both variable- and person-oriented approaches were applied. Development across several prelinguistic skills emerged as a rather continuous and stable characteristic of individual differences. Individuals differed widely in development, and six clearly distinguishable developmental trajectories were identified. Prelinguistic development was consistently related to parental and psychometric measures of later language ability and performance in working memory measures up to age 8. Growth across several prelinguistic skills was the best predictor of later language ability. The most prominent feature of developmental risk was the accumulation of early difficulties, especially if symbolic and social abilities were included. The connection between prelinguistic development and later verbal working memory was particularly strong. The findings suggest that a notable proportion of children who show multiple at-risk features of development already before their second birthday continue to show poor language and communication skills along with limitations in working memory in their later development. The findings support the rationale for early screening and indicate that features of early development that predict later development can be identified using parent reports. The key implications to screening are that assessment should cover several prelinguistic communication skills and that repeated surveillance tapping the growth of child’s skills should be favored instead of one-time screening.