Early vocabulary development benefits from diverse lexical exposures within children's language environment. However, the influence of lexical diversity on children as they enter middle childhood and are exposed to multimodal language inputs remains unclear. This study evaluates global and local aspects of lexical diversity in three…

In urban, industrialized cultures, the best predictor of how children acquire their native language is child-directed speech from adults. However, in many societies, children are much less exposed to such input. What has remained unexplored is the impact of another type of input: other children's speech. In cross-cultural head-turn experiments, we…

Studies of non-linguistic statistical learning (SL) have often linked performance in SL tasks with differences in language outcomes. Most of these studies have focused on Western and high-income educational contexts, but children worldwide learn in radically different educational systems and communities, and often in a second language. In the west…

Blind adults display language-specificity in their packaging and ordering of events in speech. These differences affect the representation of events in "co-speech gesture"--gesturing with speech--but not in "silent gesture"--gesturing without speech. Here we examine when in development blind children begin to show adult-like…

Perceptual narrowing of speech perception supposes that young infants can discriminate most speech sounds early in life. During the second half of the first year, infants' phonetic sensitivity is attuned to their native phonology. However, supporting evidence for this pattern comes primarily from learners from a limited number of regions and…

The relationship between executive function and second-language ability remains contentious in bilingual children; thus, the current study focused on this issue. In total, 371 Uyghur-Chinese bilingual children ranging from 3 to 6 years old were assessed by a battery of tasks measuring language ability (expressive vocabulary tests, receptive…

Infants undergo fundamental shifts in perception that are reported to be critical for language acquisition. In particular, infants' perception of native and non-native sounds begins to align with the properties of their native sound system. Thus far, empirical evidence for this transition--perceptual narrowing--has drawn from socio-economically…

Infant-directed speech (IDS) is phonetically distinct from adult-directed speech (ADS): It is typically considered to have special prosody--like higher pitch and slower speaking rates--as well as unique speech sound properties, for example, more breathy, hyperarticulated, and/or variable consonant and vowel articulation. These phonetic features…

Children with poor reading comprehension tend to have oral language weaknesses, suggesting that poor language in the early years is a proximal cause of later reading comprehension difficulties. Yet, longitudinal studies have not succeeded in reliably predicting which children go on to have comprehension weaknesses (CW), and evidence comprises…

The number of older siblings a child has is negatively correlated with the child's verbal skills, an effect that is well known in the literature. However, few studies have examined the effect of older siblings' sex, of the age gap between siblings, of having foreign-speaking parents, as well as the mediating role of parental interaction. Using…

Literacy is a powerful tool against poverty, leading to further education and vocational success. In sub-Saharan Africa, schoolchildren commonly learn in two languages--African and European. Multiple early literacy skills (including phonological awareness and receptive language) support literacy acquisition, but this has yet to be empirically…

Rhythm perception seems to be crucial to language development. Many studies have shown that children with developmental dyslexia and developmental language disorder have difficulties in processing rhythmic structures. In this study, we investigated the relationships between prosody and musical processing in Italian children with typical and…

In many low- and middle-income countries, young children learn a mother tongue or indigenous language at home before entering the formal education system where they will need to understand and speak a country's official language(s). Thus, assessments of children before school age, conducted in a nation's official language, may not fully reflect a…

Examining how bilingual infants experience their dual language input is important for understanding bilingual language acquisition. To assess these language experiences, researchers typically conduct language interviews with caregivers. However, little is known about the reliability of these parent reports in describing how bilingual children…

Collaboration, the process by which individuals work together toward mutual benefits, is a core feature of human sociality. Capacities for collaboration emerge early in development and represent an important social competence. Yet, collaborative commitments can conflict with commitments to societal norms such as honesty and rule compliance, and…