Longitudinal Effects on Early Adolescent Language: A Twin Study

Abstract

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.

Measuring the Impact of Genetic and Environmental Risk and Protective Factors on Speech, Language, and Communication Development-Evidence from Australia

“…In contrast to the consistent effects observed for environmental risk factors, our study found limited evidence of the impact of genetics on SLCN acquisition in infancy. These findings are consistent with the literature which investigated longitudinal patterns of speech and language acquisition using studies of twins [ 4 , 13 ]. The authors found that shared environmental influences appear to be dominant in early language, with a smaller though significant role for genetic factors [ 4 ].…”

“…There are several theoretical frameworks which seek to explain the underlying complexity of a child’s developmental landscapes [ 1 ]. In the economics literature, the “Heckman theory” or theory of “human capital development” suggests that an individual’s rate of development is determined by an initial vector of “skills and abilities”, which is largely determined by a complex interaction of biological factors (genetic, in utero environment and early infant health status) [ 2 , 3 , 4 , 5 , 6 , 7 ] and social factors (cultural, familial, socio-economic, community) [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Low language is a significant early childhood development concern, which is viewed as a “health shock” to a child’s initial vector of “skills”.…”

What Influences Speech-Language Pathologists' Use of Different Types of Language Assessments for Elementary School–Age Children?

“…These survey findings have important implications for clinical practice. Underuse of contextualized and activity-focused language assessments creates risk that language difficulties at a discourse level will be under-identified (Ebert & Scott, 2014;Harlaar et al, 2016;Thomas-Stonell et al, 2013) whilst underuse of dynamic assessments and assessments that target school and home/community contexts may lead to intervention goals and classroom supports that are not well-matched to a child's needs (Bishop & McDonald, 2009;Kover et al, 2014). Similarly, the use of norm-referenced measures rather than use of dynamic assessments with children from CALD backgrounds may lead to inappropriate conclusions being drawn regarding the language abilities of these children (Caesar & Kohler, 2007).…”

“…The ICF provides a framework for describing health and wellbeing across multiple components including Body Functions and Structures (impairment), Activities (execution of tasks), Participation (involvement in daily life activities), Environmental Factors and Personal Factors and as such, has been identified as an important framework for conceptualizing SLP assessment practice. Applying the ICF requires SLPs to use assessments that collect data on a child's performance in different types of tasks, such as de-contextualized, contextualized or activity-focused tasks (Denman et al, 2019;Harlaar et al, 2016) and on a child's performance across different environmental contexts, including a clinical context, school context or home/community context (Denman et al, 2019;Kover et al, 2014) in order to best understand a child's language performance at a holistic level (Westby, 2007). This is important as children may perform differently depending on the types of tasks targeted in an assessment (Thomas-Stonell et al, 2013;Trembath et al, 2016).…”

“…This is important as children may perform differently depending on the types of tasks targeted in an assessment (Thomas-Stonell et al, 2013;Trembath et al, 2016). For example, numerous studies have identified that children may perform differently on de-contextualized measures, such as single word vocabulary tests, when compared with contextualized procedures such as 'language sampling' (Ebert & Scott, 2014;Harlaar et al, 2016;Ukrainetz & Blomquist, 2002). Similarly, a lack of concordance between relationships in language performance as measured in clinical contexts versus school and home/community contexts, indicating that a child's communicative competence may vary depending on the environmental context in which abilities are assessed (Bishop & McDonald, 2009;Kover et al, 2014).…”