Using both online and offline measures, this study investigates how maternal education and work status (stay-at-home, part-time, full-time) are jointly associated with infants’ word learning ability and vocabulary size. One hundred 24-month-old infants completed a lab-based mutual exclusivity task, which assesses infants’ novel word learning ability. Caregivers reported infants’ productive vocabulary size using the MCDIs. There was no evidence for an association between infants’ productive vocabulary size and maternal education, maternal work status, or their interaction. However, infants’ novel word learning ability was significantly related to both maternal factors and their interaction. The positive association between maternal education and word learning performance was attenuated for infants of part-time and full-time working mothers compared to infants with at home mothers. These findings suggest that using real-time measures with high task demand may better capture developmental differences in infants and expand our understanding of maternal factors contributing to early language development.

The process by which infants learn verbs through daily social interactions is not well-understood. This study investigated caregivers’ use of verbs, which have highly abstract meanings, during unscripted toy-play. We examined how verbs co-occurred with distributional and embodied factors including pronouns, caregivers’ manual actions, and infants’ locomotion, gaze, and object-touching. Object-action verbs were used significantly more often during caregiver-infant joint attention interactions. Movement and cognition verbs showed distinct co-occurrences with different contexts. Cognition and volition verbs were differentiated by pronouns. These findings provide evidence for how verb acquisition may be supported by the distributional and embodied contexts in caregiver-infant interactions.

Children who receive cochlear implants develop spoken language on a protracted timescale. The home environment facilitates speech-language development, yet it is relatively unknown how the environment differs between children with cochlear implants and typical hearing. We matched eighteen preschoolers with implants (31-65 months) to two groups of children with typical hearing: by chronological age and hearing age. Each child completed a long-form, naturalistic audio recording of their home environment (appx. 16 hours/child; >730 hours of observation) to measure adult speech input, child vocal productivity, and caregiver-child interaction. Results showed that children with cochlear implants and typical hearing were exposed to and engaged in similar amounts of spoken language with caregivers. However, the home environment did not reflect developmental stages as closely for children with implants, or predict their speech outcomes as strongly. Home-based speech-language interventions should focus on the unique input-outcome relationships for this group of children with hearing loss.

We assess the feasibility of conducting web-based eye-tracking experiments with children using two methods of webcam-based eye-tracking: automatic gaze estimation with the WebGazer.js algorithm and hand annotation of gaze direction from recorded webcam videos. Experiment 1 directly compares the two methods in a visual-world language task with five to six year-old children. Experiment 2 more precisely investigates WebGazer.js’ spatiotemporal resolution with four to twelve year-old children in a visual-fixation task. We find that it is possible to conduct web-based eye-tracking experiments with children in both supervised (Experiment 1) and unsupervised (Experiment 2) settings – however, the webcam eye-tracking methods differ in their sensitivity and accuracy. Webcam video annotation is well-suited to detecting fine-grained looking effects relevant to child language researchers. In contrast, WebGazer.js gaze estimates appear noisier and less temporally precise. We discuss the advantages and disadvantages of each method and provide recommendations for researchers conducting child eye-tracking studies online.

Extensive research has shown that children’s early words are learned through sensorimotor experience. Thus, early-acquired words tend to have more concrete meanings. Abstract word meanings tend to be learned later but less is known about their acquisition. We collected meaning-specific concreteness ratings and examined their relationship with age-of-acquisition data from large-scale vocabulary testing with children in grade 2 to college age. Earlier-acquired meanings were rated as more concrete while later-acquired meanings as more abstract, particularly for words typically considered to be concrete. The results suggest that sensorimotor experiences are important to early-acquired word meanings, and other experiences (e.g., linguistic) are important to later-acquired meanings, consistent with a multi-representational view of lexical semantics.

Limited studies have examined demographic differences in children’s vocabulary in longitudinal samples, while there are questions regarding the duration, direction, and magnitude of these effects across development. In this longitudinal study, we included over 400 Dutch children. Caregivers filled out N-CDIs when children were 9–11 months (measuring word comprehension, word production, and gestures) and around 2–5 years of age (measuring word production). At 2–5 years, we also administered a receptive vocabulary task in the lab. We examined demographic effects on vocabulary size across infancy and toddlerhood. We found a disadvantage for males in infants’ gestures and toddlers’ vocabulary production. We found a negative effect of maternal education on infants’ caregiver-reported vocabulary, but a positive effect on toddlers’ lab-administered receptive vocabulary. Lastly, we found a negative effect of multilingualism – but only for the lab-administered task. Examining predictors in large, longitudinal samples ensures their robustness and generalisability across development.

This study investigated differences in adult-child language interactions when parents and their three-to-four-year old children engage in wordless book reading, text-and-picture book reading and a small-world toy play activity. Twenty-two parents recorded themselves completing each activity at home with their child. Parent input was compared across contexts, focusing on interactive and conceptual domains: use of open prompts, expansions or extensions of children’s utterances, and use of decontextualised (abstract) language. Use of linguistic expansions was greater during book reading than toy play. Parents used open questions and added contingent conceptual information more often when reading wordless books than in both other conditions. Findings suggest that wordless books may combine the benefits of open-endedness and linguistic content based around a narrative. Parents’ use of abstract language also varied by condition. This study extends understanding of the role of activity context in shaping children’s language learning environments.

We investigated older children’s (7–12 years) ability to comprehend before and after sentences. Results found that three factors that influence pre-school aged children’s learning of these words continues to influence older children’s comprehension. Specifically, children’s accuracy is improved when the events can be naturally (vs. arbitrarily) ordered; when the clauses in the sentence iconically match (vs. mismatch) the order of the events in the world; and when sentences use before (vs. after). The first two factors are argued to directly facilitate the building of mental models while the last one does so indirectly because of patterns of input usage.

This study compared a unidimensional model of vocabulary and a two-factor model comprising vocabulary breadth and depth in a second language (L2). A total of 167 Chinese Grade 4 and 5 primary school children (Meanage = 9.96 years old) learning English as an L2 participated in this study, and they were tested on four English vocabulary tests. Our results of confirmatory factor analyses indicate that vocabulary breadth and depth were not two distinct dimensions, and the unidimensional model was supported. Theoretical and practical implications were discussed.

This research investigated the impact of the number of talkers with whom children engage in daily conversation on their language development. Two surveys were conducted in 2020, targeting two-year-olds growing up in Japanese monolingual families. Caregivers reported the number of talkers in three age groups and children’s productive vocabulary via questionnaires. The results demonstrated significant effects of variability in talkers in fifth grade or above in Study 1 (N = 50; male = 23; r = .372) and in adult talkers in Study 2 (N = 175; non-nursery going; male = 76; r = .184) on children’s vocabulary development, after controlling for language exposure time and demographic variables. Possible mediating factors are discussed. This research extends previous findings from immigrant bilingual children to monolingual speakers in Japan, suggesting the potential contribution of available talkers other than caregivers in conversational environments.

This study assessed the relationship between preschoolers’ directly and indirectly assessed emotion word comprehension. Forty-nine two-to-five-year-old Norwegian children were assessed in a tablet-based 4-alternative forced choice (AFC) task on their comprehension of six basic and six complex emotions using facial expression photographs. Parents reported emotion word comprehension and production of the same words. Parent-reported emotion word production interacted with age to predict preschoolers’ performance, with a parent-child alignment only observed for older children. Parent-reported word comprehension did not significantly predict accuracy. The results suggest that, in preschoolers, direct and indirect assessments might address distinct representational levels of emotion word comprehension.