The speech register that adults especially caregivers use when interacting with infants and toddlers, that is, infant-directed speech (IDS) or baby talk, has been reported to facilitate language development throughout the early years. However, the neural mechanisms as well as why IDS results in such a developmental faciliatory effect remain to be…

Purpose: The Language ENvironment Analysis (LENA) technology uses automated speech processing (ASP) algorithms to estimate counts such as total adult words and child vocalizations, which helps understand children's early language environment. This ASP has been validated in North American English and other languages in predominantly monolingual…

This article explores the applicability of mean length of utterance (MLU) as a language assessment measure for Georgian child language, as to-date, Georgian, a morphologically rich language with numerous inflectional categories, experiences an extensive lack of instruments for early language assessment. To this end, a set of guidelines for…

Children's vocabulary ability at school entry is highly variable and predictive of later language and literacy outcomes. Sleep is potentially useful in understanding and explaining that variability, with sleep patterns being predictive of global trajectories of language acquisition. Here, we looked to replicate and extend these findings. Data from…

The Babysong Project arose out of the Baby Room Project and its aims included supporting baby room practitioners to develop 'communicative musicality' (Malloch & Trevarthen 2009), extending research knowledge about baby room practices and helping practitioners to explore opportunities to question and adapt their own ways of working with babies…

This article evaluates the acquisition of directionals in Q'anjob'al, a Western Mayan language of Guatemala. The data come from a longitudinal study of two Q'anjob'al monolingual children of Santa Eulalia, Huehuetenango, Guatemala: Xhuw (1;9-2;5) and Xhim (2;3-3;5). The results show how these children acquire the morphological distribution of…

Objective: The tendency to vocalize toward objects is ubiquitous among young infants. However, little is known about the range of this tendency and its contribution to language development. Therefore, this longitudinal study objective was to explore the role of three forms of vocal behavior (vocalization, babbling, and speech) directed toward…

Infants begin to understand some of the meanings of the adjective "good" at around thirteen months, but it is not clear when they start to map it to concepts in the moral domain. We investigated infants' and toddlers' knowledge of "good" in the domains of help and fairness. Participants at 20 and 30 months were shown computer…

Purpose: Fathers play a critical but underresearched role in their children's cognitive and linguistic development. Focusing on two-parent families with a mother and a father, the present longitudinal study explores the amount of paternal input infants hear during the first 2 years of life, how this input changes over time, and how it relates to…

Lexical iconicity--signs or words that resemble their meaning--is overrepresented in children's early vocabularies. Embodied theories of language acquisition predict that symbols are more learnable when they are grounded in a child's firsthand experiences. As such, pantomimic iconic signs, which use the signer's body to represent a body, might be…

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…

In languages with evidential marking, utterances consist of an informational content and a specification of the mode of access to that information. In this first longitudinal study investigating the acquisition of the Turkish evidential marker "-mIs" in naturalistic child-caregiver interactions, we examined six children between 8 and 36…

For children with normal hearing (NH), early communication skills predict vocabulary, a precursor to grammar. Growth in early communication skills of infants with cochlear implants (CIs) was investigated using the Early Communication Indicator (ECI), a play-based observation measure. Multilevel linear growth modelling on data from six ECI sessions…

This study evaluated the impact of a parenting intervention on children's cognitive and socioemotional development in a group of caregivers and their 21-to-28-month-old children in a low-income South African township. A randomized controlled trial compared an experimental group (n = 70) receiving training in dialogic book-sharing (8 weekly group…

Previous work suggests that key factors for replicability, a necessary feature for theory building, include statistical power and appropriate research planning. These factors are examined by analyzing a collection of 12 standardized meta-analyses on language development between birth and 5 years. With a median effect size of Cohen's d = 0.45 and…