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 a seminal study, Cameron-Faulkner et al. made two important observations about utterance-level constructions in English child-directed speech (CDS). First, they observed that canonical in/transitive sentences are surprisingly infrequent in child-direct speech (given that SVO word order is often thought to play a key role in the acquisition of…

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…

Children learn language by listening to speech from caregivers around them. However, the type and quantity of speech input that children are exposed to change throughout early childhood in ways that are poorly understood due to the small samples (few participants, limited hours of observation) typically available in developmental psychology. Here…

Purpose: Talkers adapt their speech according to the demands of their listeners and the communicative context, enhancing the properties of the signal (pitch, intensity) and/or properties of the code (enhancement of phonemic contrasts). This study asked how mothers adapt their child-directed speech (CDS) in ways that might serve the immediate goals…

Causation is a core feature of human cognition and language. How children learn about intricate causal meanings is yet unresolved. Here, we focus on how children learn verbs that express causation. Such verbs, known as lexical causatives (e.g., break and raise), lack explicit morphosyntactic markers indicating causation, thus requiring that the…

Purpose: Disfluencies can be classified as stuttering-like disfluencies (SLDs) or typical disfluencies (TDs). Dividing TDs further, stalls (fillers and repetitions) are thought to be prospective, occurring due to planning glitches, and revisions (word and phrase revisions, word fragments) are thought to be retrospective, occurring when a speaker…

This study focuses on parental use of parentese: the acoustically exaggerated, clear, and higher-pitched speech produced by adults across cultures when they address infants. While previous research shows that parentese enhances language learning and processing, it is still unclear what drives the variability in the amount of parental parentese…

In early childhood centres, decontextualised talk is often associated with literacy activities. In this study, however, we investigated toddler-educator conversations across various activities with a focus on those about topics that were not related to the immediate context. We examined the communicative purposes and linguistic features of these…

We investigated the effect of part of speech adoption on the utterance length of Mandarin-speaking children. A total of 209 typically developing Taiwanese children aged 3-6 years participated in the study. They included 90 boys and 119 girls recruited from preschools in Miaoli City, New Taipei City, and Taipei City. We collected children's…

Child-directed speech has long been known to influence children's vocabulary learning. However, while we know that caregiver utterances differ from those directed at adults in various ways, little is known about any differences in the lexical properties of child-directed and adult-directed utterances. We compare over half a million word tokens…

Purpose: The purpose of the present study was to examine whether there is a listening preference for child-directed speech (CDS) over backward speech in moderate-preterm infants (MPIs). Method: Eighteen MPIs of gestational age of 32.0 weeks (range: 32-34.06 weeks), chronological age of 8.09 months, and maturation age of 6.48 months served as the…

This study investigated why object-gap relative clauses (RCs) are dominant in early child Mandarin. We discuss how restrictive-RCs differ from pseudo-RCs syntactically and pragmatically, and examine how these two types of RCs are distributed in the RC utterances of ten children and their caregivers. The results showed that (a) Mandarin-speaking…

The acquisition of quantifiers is a central topic in cognitive science. The present study investigated the emergence, frequency, and non-target-like production of the universal quantifiers "all," "every," and "each" in child English from a linguistic perspective, based on the data from longitudinal naturalistic…

Research on "parentese," the acoustically exaggerated, slower, and higher-pitched speech directed toward infants, has mostly focused on maternal contributions, although it has long been known that fathers also produce parentese. Given recent societal changes in family dynamics, it is necessary to revise these mother-centered models of…