During the recent pandemic, it became necessary to adapt lab-based studies to online experiments. To investigate the impact of online testing on the quality of data, we focus on three paradigms widely used in infant research: a word recognition task using the Intermodal Preferential Looking Paradigm, a word learning task using the Switch task, and a language assessment tool (WinG) where children identify a target word amongst a set of picture cards. Our results for synchronous and asynchronous studies provide support for the robustness of online testing. In Experiment 1, robust word recognition was found in 24-month-old toddlers. In Experiment 2, 17-month-old infants consistently learned a new word. Finally, Experiment 3 demonstrated that 19- to 26-month-old children performed well on a language assessment test administered online. Overall, effect sizes or language scores were found to be higher than in lab-based studies. These experiments point to promising possibilities for reaching out to families around the world.

Many studies have explored children’s acquisition of temporal adverbs. However, the extent to which children’s early temporal language has discursive instead of solely temporal meanings has been largely ignored. We report two corpus-based studies that investigated temporal adverbs in Finnish child-parent interaction between the children’s ages of 1;7 and 4;11. Study 1 shows that the two corpus children used temporal adverbs to construe both temporal and discursive meanings from their early adverb production and that the children’s usage syntactically broadly reflected the input received. Study 2 shows that the discursive uses of adverbs appeared to be learned from contextually anchored caregiver constructions that convey discourse functions like urging and reassuring, and that the usage is related to the children’s and caregivers’ interactional roles. Our study adds to the literature on the acquisition of temporal adverbs by demonstrating that these items are learned also with additional discursive meanings in family interaction.

This study mapped the trajectory of developing derivational morphological knowledge in Hebrew monolingual and Russian–Hebrew bilingual children. We investigated 2nd and 4th graders, using a two-by-two structure along the dimensions of modality (comprehension, production) and type of word (real-word, pseudo-word). Performance in the morphological analogies comprehension tasks improved with grade, and monolingual and bilingual children performed equally well. A different pattern was evident in production tasks. In real-word production, monolingual children were more accurate than bilingual children, but this group difference narrowed with age. In pseudo-word production, monolingual children used more morphological elements than bilingual children, and there was also a tendency towards group differences narrowing with age. Detailed error analyses across all tasks revealed that monolingual children recruited more morphological elements than bilingual children. We present implications for assessment of morphological knowledge, and suggest that morphological intervention is a promising avenue for promoting bilingual children’s success.

This scoping review aimed to investigate the communication strategies utilized by children who acquire a minority language (L1) and subsequently learn a community language (L2) during what is commonly referred to as the “silent period.” Electronic database searches were conducted using keywords such as “silent period” and “bilingual children,” resulting in the inclusion of 40 studies in the review. The findings revealed that emergent bilingual children utilize various communication strategies, including nonverbal communication, private speech, and their L1, to communicate within classroom environments. The findings shed light on the adaptability of emergent bilingual children during early stage of L2 acquisition. Furthermore, our review provides information about the classroom contexts such as teacher support and peer interactions where children develop their L2 skills. From a clinical perspective, recognizing these strategies and classroom contexts could significantly enhance the screening process for emergent bilingual children.

We examined the neurophysiological underpinnings of lexical-tone and vowel-quality perception in learners of a non-tonal language. We tested 25 6- and 25 9-month-old German-learning infants, as well as 24 German adults and expected developmental differences for the two linguistic properties, as they are both carried by vowels, but have a different status in German. In adults, both lexical-tone and vowel-quality contrasts elicited mismatch negativities, with a stronger response to the vowel-quality contrast. Six-month-olds showed positive mismatch responses for lexical-tone and vowel-quality contrasts, with an emerging negative mismatch response for vowel-quality only. The negative mismatch responses became more pronounced for the vowel-quality contrast at 9 months, while the lexical-tone contrast elicited mainly positive mismatch responses. Our data reveal differential developmental changes in the processing of vowel properties that differ in their lexical relevance in the ambient language.

Children up to school age are known to have difficulty comprehending complex sentences with temporal connectives, but the reasons remain controversial. We tested six- to twelve-year-old children to assess how the iconicity of event-language mapping, type of connective, and clause order mediate the comprehension of temporal sentences. Sixty monolingual Greek-speaking children and 15 adult controls completed a picture-sequence selection task in which they judged after- and before-sentences in iconic and non-iconic order. Up to age twelve, children did not reach full adult-like comprehension of the connectives; performance in non-iconic after-sentences was significantly lower than in the other three conditions across all ages. We conclude that neither iconicity, connective, nor clause order can fully explain these findings and propose an account based on the interaction of iconicity and clause order: non-iconic, sentence-medial after requires revision of the initial event representation, resulting in an event-semantic kindergarten-path that children find difficult to overcome.

This study explored monolingual and multilingual two- to five-year-olds’ reliance on a non-verbal and a verbal cue during word-referent mapping, in relation to vocabulary knowledge and, for the multilinguals, Dutch language exposure. Ninety monolingual and sixty-seven multilingual children performed a referential conflict experiment that pitted a non-verbal (pointing) cue and a verbal (mutual exclusivity) cue. Mixed-effect regressions showed no main effects of vocabulary and language exposure. An interaction between vocabulary and group showed that lower vocabulary scores were associated with a stronger reliance on pointing over mutual exclusivity for multilinguals (but not monolinguals). Furthermore, an interaction between vocabulary, language exposure, and cue word (novel vs. familiar label) indicated that multilinguals with lower exposure and lower vocabulary showed a stronger reliance on pointing over mutual exclusivity when a novel rather than familiar word was used. These findings suggest that multilingual and monolingual children go through different trajectories when learning to map words to referents.

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.

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 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.