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Purpose: We evaluated genetic and environmental contributions to individual differences in language skills during early adolescence, measured by both language sampling and standardized tests, and examined the extent to which these genetic and environmental effects are stable across time. Method: We used structural equation modeling on latent factors to estimate additive genetic, shared environmental, and nonshared environmental effects on variance in standardized language skills (i.e., Formal Language) and productive language-sample measures (i.e., Productive Language) in a sample of 527 twins across 3 time points (mean ages 10-12 years). Results: Individual differences in the Formal Language factor were influenced primarily by genetic factors at each age, whereas individual differences in the Productive Language factor were primarily due to nonshared environmental influences. For the Formal Language factor, the stability of genetic effects was high across all 3 time points. For the Productive Language factor, nonshared environmental effects showed low but statistically significant stability across adjacent time points. Conclusions: The etiology of language outcomes may differ substantially depending on assessment context. In addition, the potential mechanisms for nonshared environmental influences on language development warrant further investigation. [ABSTRACT FROM AUTHOR]

Purpose: The existing literature on language outcomes in children born prematurely focuses almost exclusively on standardized test scores rather than discourse-level abilities. The authors of this study looked longitudinally at school-age language outcomes and potential moderating variables for a group of twins born prematurely versus a control group of twins born at full term, analyzing both standardized test results and language sample data from the population-based Western Reserve Reading Project (WRRP; Petrill, Deater- Deckard, Thompson, DeThorne, & Schatschneider, 2006). Method: Fifty-seven children born prematurely, at ≤32 weeks or <1,500 g, were compared with 57 children born at full term and were matched for age, gender, race, and parental education. Data included discourse-level language samples and standardized test results, collected at average ages 7, 8, and 10 years. The language samples were analyzed to yield a number of semantic and syntactic measures that were consolidated via factor analysis. Results: Regression models showed significant differences between the 2 groups for standardized test results, although the mean score for both groups fell in the normal range. For the discourse-level language measures, however, differences never reached statistical significance. Parental education was significantly associated with improved standardized test scores. Conclusions: These findings suggest that in the absence of frank neurological impairment, sophisticated semantic and syntactic skills may be relatively intact in the discourse-level language of children born prematurely. Implications for assessment, particularly the potential role of attention and executive function in standardized testing tasks, are reviewed. [ABSTRACT FROM AUTHOR]