Background: One of the most significant developmental accomplishments is the emergence of language in early childhood. Whilst this process is effortless for most children, others can face significant hurdles. Identifying, in the early years, which children will go on to have developmental language disorder is, however, fraught with several…

For the past 25 years, researchers have investigated language input to children from high- and low-socioeconomic status (SES) families. Hart and Risley first reported a "30 Million Word Gap" between high-SES and low-SES children. More recent studies have challenged the size or even existence of this gap. The present study is a…

We provide an account of the developmental trajectory of Emirati Arabic negation particles. We treat the non-verbal predicate negator (NVPN) "mub" as a negative copula, in contrast to the verbal predicate negator (VPN) "maa," which encodes sentential negation in verbal and existential contexts. The analysis is supported by…

Research Findings: Early childhood teachers' talk is a key ingredient in children's early language and literacy development, but there has been little systematic synthesis of observational studies that examine relationships between teacher talk and child oral language. In this systematic review of 54 studies, we investigate and synthesize the…

This meta-analysis examined associations between the quantity and quality of parental linguistic input and children's language. Pooled effect size for quality (i.e., vocabulary diversity and syntactic complexity; k = 35; N = 1,958; r = .33) was more robust than for quantity (i.e., number of words/tokens/utterances; k = 33; N = 1,411; r = .20) of…

We conducted a systematic review to identify randomized controlled trials (RCTs) and single case research design (SCRD) studies of children with autism spectrum disorder that evaluate the effectiveness of responsivity intervention techniques for improving prelinguistic and/or language outcomes. Mean effect sizes were moderate and large for RCTs…

This meta-analysis aims to clarify the relationship between teacher-child interaction and children's outcomes in language, mathematics, literacy, social development, and self-regulation based on the perspective of the Classroom Assessment Scoring System (CLASS). A total of 24 studies with 139 independent effect sizes and 67,919 participants were…

In this article, we provide an overview of the last twenty years of research on Indigenous sign languages, deaf community sign languages, co-speech gesture, and multimodal communication in the Australian context. From a global perspective, research on sign languages and on the gestures that normally accompany speech has been used as the basis for…

A comprehensive theory of child language acquisition requires an evidential base that is representative of the typological diversity present in the world's 7000 or so languages. However, languages are dying at an alarming rate, and the next 50 years represents the last chance we have to document acquisition in many of them. Here, we take stock of…

Children's speech development begins in infancy. The pattern of this development has been explored in studies over a number of years using a range of research methodology and approaches to investigation. A systematic review of the existing literature was carried out to determine the collective contribution of this literature to our understanding…

Background: The emergence of language in the early years is a major developmental accomplishment that underpins learning, enables social interaction and, later, is an indicator of well-being. Learning language is an effortless process for most, but can be challenging for others. There is a need to act early. First, because there are several…

Interventions that train parents to share picture books with children are seen as a strategy for supporting child language development. We conducted meta-analyses using robust variance estimation modeling on results from 19 RCTs (N[subscript total] = 2,594; M[subscript child age] = 1-6 years). Overall, book-sharing interventions had a small sized…

Over the past 2 decades, a growing number of randomised controlled trials have assessed the impact on children's language skills of interventions encouraging parents to read books to their offspring. We present the results of a meta-analysis of the impact of 30 such interventions. Results indicate that they are often ineffective, and that only one…

This review article presents evidence for the claim that frequency effects are pervasive in children's first language acquisition, and hence constitute a phenomenon that any successful account must explain. The article is organized around four key domains of research: children's acquisition of single words, inflectional morphology, simple…

Language exerts a powerful influence on our concepts. We review evidence documenting the developmental origins of a precocious link between language and object categories in very young infants. This collection of studies documents a cascading process in which early links between language and cognition provide the foundation for later, more precise…