Longitudinal Effects on Early Adolescent Language: A Twin Study.

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.

Breastfeeding and language outcomes: A review of the literature.

UNLABELLED: Many researchers have investigated the potential impact of breastfeeding in infancy on a child's subsequent development, but only a small subset of these studies considers language development and impairment. This paper reviews that literature, discussing postnatal neurodevelopment, potential mechanisms for dietary influences on communication outcomes, studies of typically developing children, and studies of children with communication concerns. For population based studies of language development, a modest but statistically robust relationship is seen across large samples that account for breastfeeding exclusivity. A similar protective relationship is seen in studies that evaluate the relationship between breastfeeding and language disorders; effect sizes are typically larger in these papers. Implications for researchers and service providers are reviewed. LEARNING OUTCOMES: Readers will be able to describe possible mechanisms by which early diet might influence neurodevelopment. They will be able to describe the relationships observed between diet in infancy and language outcomes in large population-based studies, as well as the trends observed in studies of the relationship between infant diet and communication impairment.

From aardvark to ziggurat: A new tool for assessing children's use of rare vocabulary.

This study introduces a resource for examining children's use of low-frequency vocabulary and describes preliminary evidence of its validity. Using a corpus of >1400 transcripts from school-aged children, we derived a concordance of all words spoken by the children and generated a list of 2079 uncommon words we have called WERVE, the Wordlist for Expressive Rare Vocabulary Evaluation. Preliminary validity evidence for WERVE was examined through correlation analyses with WERVE results and other common language measures in a test sample of 112 children age 7 and 8 years. In addition, we replicated the correlation analyses using a sample of 38 eight-year-old children. WERVE results correlated strongly with established language sample measures and to a lesser but frequently significant degree with standardized test results. Results also showed developmental change from age 7 to age 8. Correlations ranged from medium to large. These results suggest that WERVE may be a useful tool for language sample researchers to explore.

Impact of prematurity on language skills at school age.

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.