Purpose: This study investigates the heritability of language, speech, and nonverbal cognitive development of twins at 4 and 6 years of age. Possible confounding effects of twinning and zygosity, evident at 2 years, were investigated among other possible predictors of outcomes. Method: The population-based twin sample included 627 twin pairs and 1…

Background: Population-based studies have found that early language delays are associated with poorer long-term outcomes in adolescence and adulthood. Few studies have explored the influence of change in language ability over time on adult outcomes. Aim: To examine the educational, vocational and mental health outcomes for adults accounting for…

Vocabulary knowledge is a critical component of school readiness. The current study investigated the extent to which low levels of joint attention in infancy and parent-child book reading across early childhood increase the risk of children having poor vocabulary around the time of school entry. Relevant data from the Longitudinal Study of…

The genetic factor structure of a range of learning measures was explored in twin children, recruited in preschool and followed to Grade 2 ("N"?=?2,084). Measures of orthographic learning and word reading were included in the analyses to determine how these patterned with the learning processes. An exploratory factor analysis of the…

Parents of children with suspected Childhood Apraxia of Speech (sCAS, n = 20), Specific Language Impairment (SLI, n = 20), and typically developing speech and language skills (TD, n = 20) participated in this study, which aimed to quantify and compare reports of early vocal development. Via a questionnaire, parents reported on their child's early…

In this 3-year longitudinal study, the authors tested and extended M. Senechal and J. Le Fevre's (2002) model of the relationships between preschool home literacy practices and children's literacy and language development. Parent-child reading (Home Literacy Environment Questionnaire plus a children's Title Recognition Test) and parental teaching…

Preliminary results from data on 146 Australian, 284 American, and 70 Norwegian preschool twins indicate reliable genetic influences on phonological awareness and memory and learning. Vocabulary, grammar, and morphology showed significant shared environment and negligible genetic effects. A print knowledge composite showed genetic and shared…