Everyday language input and production in 1,001 children from six continents

Estimating Age-Related Change in Infants' Linguistic and Cognitive Development Using (Meta-)Meta-Analysis

Developmental psychology focuses on how psychological constructs change with age. In cognitive development research, however, the specifics of this emergence is often underspecified. Researchers often provisionally assume linear growth by including chronological age as a predictor in regression models. In this work, we aim to evaluate this assumption by examining the functional form of age trajectories across 25 phenomena in early linguistic and cognitive development by combining the results of multiple meta-analyses in Metalab, an open database. Surprisingly, for most meta-analyses, the effect size for the phenomenon did not change meaningfully across age. We investigated four possible hypotheses explaining this pattern: (1) age-related selection bias against younger infants; (2) methodological adaptation for older infants; (3) change in only a subset of conditions; and (4) positive growth only after infancy. None of these explained the lack of age-related growth in most datasets. Our work challenges the assumption of linear growth in early cognitive development and suggests the importance of uniform measurement across children of different ages.

Accent variation and the development of speech and language abilities

Accent variation is a central feature of human language. As adults, we readily adapt to different varieties of our native language, but we also use accent information to make a variety of social inferences. Thus, our treatment of accents sits squarely at the intersection of language and social processing. Despite the ubiquity of accent variation and its importance in our mental lives, it was long absent from studies in the field of infant development. Although the complexities of bilingual input were recognized, the study of monolingual language development proceeded as if all infants were exposed to a single variety of their native language. This perspective shaped our theories of speech and language development. The first study to explore infants' perception of accents was published in 2000. Over the past 25 years, there has been a steady increase in work on infants' treatment of new accent varieties, their handling of multiple varieties in their natural input, and their accent-based social inferences. There is much left to be learned about just how infants navigate the rich tapestry of speech variation in their environments, but this work has already provided an important window into the nature of infants' speech representations and has upended our understanding of how early links between language and social variation are formed. We conclude our review by highlighting how understanding infants' treatment of accent variation is critical for developing models that can account for efficient speech and language development in linguistically diverse contexts.

From data to discovery: Technology propels speech-language research and theory-building in developmental science

Research on speech and language development has a long history, but in the past decade, it has been transformed by advances in recording technologies, analysis and classification tools, and AI-based language models. We conducted a systematic literature review to identify recently developed (semi-)automatic tools for studying speech-language development and learners' environments in infants and children under the age of 5 years. The Language ENvironment Analysis (LENA) system has been the most widely used tool, with more and more alternative free- and/or open-source tools emerging more recently. Most studies were conducted in naturalistic settings, mostly recording longer time periods (daylong recordings). In the context of vulnerable and clinical populations, most research so far has focused on children with hearing loss or autism. Our review revealed notable gaps in the literature regarding cultural, linguistic, geographic, clinical, and social diversity. Additionally, we identified limitations in current technology-particularly on the software side-that restrict researchers from fully leveraging real-world audio data. Achieving global applicability and accessibility in daylong recordings will require a comprehensive approach that combines technological innovation, methodological rigour, and ethical responsibility. Enhancing inclusivity in participant samples, simplifying tool access, addressing data privacy, and broadening clinical applications can pave the way for a more complete and equitable understanding of early speech and language development. Automatic tools that offer greater efficiency and lower cost have the potential to make science in this research area more geographically and culturally diverse, leading to more representative theories about language development.

Early Vocabulary Acquisition: From Birth Order Effect to Child-to-Caregiver Ratio

Growing up with multiple siblings might negatively affect language development. This study examined the associations between birth order, sibling characteristics and parent-reported vocabulary size in 6163 Norwegian 8- to 36-month-old children (51.4% female). Results confirmed that birth order was negatively associated with vocabulary, yet exhibited a U-shaped pattern. A data-driven measure of "child-to-caregiver ratio" in the household was developed, in which old-enough siblings-females 1-3 years earlier than males-were considered caregivers for their younger siblings. This measure explained variance in vocabulary better than birth order, and indicates sex-differences in the age at which older siblings contribute to, rather than deplete, available resources. A child-to-caregiver ratio might better capture the interplay between language-learning resources and demands within households.

Examining Dutch children's vocabularies across infancy and toddlerhood: Demographic effects are age-specific and task-specific

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.

Demographic Biases in Naturalistic Language Recordings in the CHILDES Database

In recent years, the importance of estimating demographic biases in research has become apparent. Here, we provide a systematic review of the CHILDES database, the major source of naturalistic recordings of children's linguistic environment. We analyzed the database according to four dimensions considered central to language learning: SES, urbanization, family structure, and language. We present descriptive statistics of each dimension to assess whether naturalistic recordings were biased regarding the demographics of the countries and the families recorded within them. We find that CHILDES's recordings overrepresented wealthier countries and higher parental education levels, urban settings, and smaller households. Middle- and higher-class participants were likewise over-represented. The corpora were not representative of their countries in terms of urbanization either-with a larger percentage of families residing in urban settings than is overall true for their respective countries. In terms of family structure, nuclear families were more prevalent than in the countries where the data were collected. Last, we found that corpora were linguistically diverse, but we estimate that these recordings underrepresented bilingual and multilingual households. We conclude that researchers should be mindful when generalizing from naturalistic recordings of children's input and output obtained from CHILDES and make recommendations for the future use of CHILDES.

Validation of the Language ENvironment Analysis in Swedish Children

PURPOSE

The Language ENvironment Analysis (LENA) is a technological tool designed for comprehensive recordings and automated analysis of young children's daily language and auditory environments. LENA recordings play a crucial role in both clinical interventions and research, offering insights into the amount of spoken language children are exposed to in their homes, including adult word count (AWC) and child vocalization count (CVC). Although LENA was initially developed for American English, it has been validated in various other languages. This study aimed to evaluate the reliability of LENA in a Swedish context by comparing its automatic estimates with human transcriptions.

METHOD

Thirty-six children aged 11-29 months participated in the validation study. A total of 540 min (9 hr) of recordings were transcribed by one experienced speech-language pathologist and two special educators. Interrater agreement over 150 min was notably higher for CVC (intraclass correlation coefficient [ICC] = .97, 95% confidence interval [CI] [.91, .99], r = .96, p < .001) compared to AWC, which yielded an ICC of .82 (95% CI [.15, .96], r = .80, p = .006).

RESULTS

Both estimated CVC and AWC (n = 36) were significantly correlated with human transcriptions (r = .79 and .82, respectively; p < .001).

CONCLUSIONS

The findings align with prior validation studies, indicating that LENA is suitable for use in a Swedish context, particularly for families with children aged 11-29 months. Nonetheless, additional validation studies are necessary, particularly focusing on younger infants, to enhance our understanding of the tool's reliability in preverbal children and their caregivers.

Hearing Early Opens More Doors: Long-Term Effects of Age at Implantation on Metaphor Comprehension in Adolescents and Young Adults With Cochlear Implants

PURPOSE

There is solid evidence that an early age at cochlear implantation, which reduces the period of auditory deprivation, positively impacts early spoken language development. However, there is an urgent need for more research to understand the long-term effects of early implantation on higher linguistic skills, such as metaphor comprehension. In this study, we explored metaphor comprehension in Swedish-speaking adolescents and young adults with cochlear implant (CI), compared to that of typically hearing peers, as well as its relationship with the age at first CI.

METHOD

The participants consisted of 39 individuals who received CI before 30 months of age (Mage = 16.9 years, mean age at implant = 15.7 months) and a group of 27 individuals with typical hearing (Mage = 14.9 years). To assess metaphor comprehension, we developed a multiple-choice task that was administrated verbally. Standardized tests were used to evaluate vocabulary, reading skills, and nonverbal cognitive skills.

RESULTS

No significant differences were found in metaphor comprehension or other linguistic or cognitive skills between individuals with CI and the typically hearing peers. Further analysis indicated a moderate negative correlation between metaphor comprehension and age at implantation and other linguistic skills.

CONCLUSIONS

Early-implanted children develop metaphor comprehension comparable to their typically hearing peers, with earlier age at implantation being associated with better metaphor comprehension in adolescence. However, age at implantation only partially explains the variation in metaphor comprehension abilities. Further research is needed to identify other factors that influence the development of metaphor comprehension in individuals with CI.

Parental Social and Musical Characteristics, the Home Music Environment, and Child Language Development in Infancy

Parents use music, especially singing, to interact with their young children, supporting parent-child bonding and social communication. Little is known about the parental attributes that support musical interactions with their infants. In this exploratory study, we analyzed self-report data from 43 caregiver/infant dyads at up to four time points (9, 12, 15, and 18 months) to assess parent social motivation and musical training as predictors of the home music environment overall, parental singing, and parental beliefs in the benefits of music. We also investigated the home music environment as a predictor of language development longitudinally. Parent social motivation was a stronger predictor of the home music environment than musical training. Parents' social motivation was positively related to parental singing, beliefs, and overall music environment, while musical training was only related to their beliefs. Furthermore, parent singing and overall home music, but not parental beliefs, were associated with infants' vocabulary comprehension, production, and gestures. Results highlight that music engagement in early childhood is fundamentally a social experience and emphasize the importance of parents' active participation (vs. only their beliefs) in musical experiences with their infant. The social nature of music experiences in infancy may contribute to relationships between the home music environment and child language development.

Socioeconomic Status Predicts Infant Word Recognition: Evidence From a Linguistically, Ethnically, and Socioeconomically Diverse Community Sample in Singapore

Prior research has demonstrated that infants have the capacity to recognize some familiar words. However, past studies have not analyzed the sociodemographic generalizability of research findings. In the current study, we examine word recognition in a linguistically, ethnically, and socioeconomically diverse community sample. A community sample of Singaporean infants from diverse socioeconomic and linguistic backgrounds between 5 and 12 months of age were tested on their ability to recognize common nouns in a looking-while-listening task. Results revealed that parental socioeconomic status, the amount of exposure to English, and infants' age significantly predicted their word recognition performance. A subsequent sensitivity analysis revealed that the effects of SES and age on word recognition were robust. The results demonstrate that socioeconomic status contributes significantly to variation in infants' abilities to recognize familiar words. Findings emphasize the importance of integrating and analyzing effects of sociodemographic representation into studies on infant word learning.

Immature vocalizations elicit simplified adult speech across multiple languages

Learning to speak takes place during a prolonged period of immaturity, which confers advantages for communicative development. Social partners, required for survival in early development, afford feedback for immature vocalizations like babbling and early speech. Feedback, in the form of changes to the linguistic structure of adult speech in response to infant vocalizations, may guide the earliest stages of language acquisition. In a cross-linguistic study of 1,586 transcripts, spanning 13 languages from 5 language families, we investigated whether caregiver talk was consistently influenced by children's (aged 5-30 months) immature speech. Across languages, we found that most caregivers significantly simplified their linguistic structure in response to children's immature speech, resulting in reduced lexical diversity, shorter utterance lengths, and higher likelihoods of single-word utterances. Children's vocalizations elicited learnable language from caregivers, highlighting a potentially widespread feature of language use that is catalyzed by immature behavior. Thus, altriciality allows for immature speech to be a social tool, creating opportunities for learning during social interaction.

Validation of the Language ENvironment Analysis (LENA) Automated Speech Processing Algorithm Labels for Adult and Child Segments in a Sample of Families From India

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 contexts but not in a multilingual context like India. Thus, the current study aims to validate the classification accuracy of the LENA algorithm specifically focusing on speaker recognition of adult segments (AdS) and child segments (ChS) in a sample of bi/multilingual families from India.

METHOD

Thirty neurotypical children between 6 and 24 months (M = 12.89, SD = 4.95) were recruited. Participants were growing up in bi/multilingual environment hearing a combination of Kannada, Tamil, Malayalam, Telugu, Hindi, and/or English. Daylong audio recordings were collected using LENA and processed using the ASP to automatically detect segments across speaker categories. Two human annotators manually annotated ~900 min (37,431 segments across speaker categories). Performance accuracy (recall and precision) was calculated for AdS and ChS.

RESULTS

The recall and precision for AdS were 0.62 (95% confidence interval [CI] [0.61, 0.63]) and 0.83 (95% CI [0.8, 0.83]), respectively. This indicated that 62% of the segments identified as AdS by the human annotator were also identified as AdS by the LENA ASP algorithm and 83% of the segments labeled by the LENA ASP as AdS were also labeled by the human annotator as AdS. Similarly, the recall and precision for ChS were 0.65 (95% CI [0.64, 0.66]) and 0.55 (95% CI [0.54, 0.56]), respectively.

CONCLUSIONS

This study documents the performance of the ASP in correctly classifying speakers as adult or child in a sample of families from India, indicating recall and precision that is relatively low. This study lays the groundwork for future investigations aiming to refine the algorithm models, potentially facilitating more accurate performance in bi/multilingual societies like India.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27910710.

Early trajectories and moderators of autistic language profiles: A longitudinal study in preschoolers

LAY ABSTRACT

Language development can greatly vary among autistic children. Children who struggle with language acquisition often face many challenges and experience lower quality of life. However, little is known about the early language trajectories of autistic preschoolers and their moderators. Autistic language can be stratified into three profiles. Language unimpaired experience little to no language difficulties; language impaired show significant difficulties in language; minimally verbal never develop functional language. In this study, we used a longitudinal sample of preschoolers with autism and with typical development (aged 1.5-5.7 years). We replicated the three language profiles through a data-driven approach. We also found that different factors modulated the language outcome within each group. For instance, non-verbal cognition at age 2.4 moderated the participants' attribution to each language profile. Moreover, early intervention moderated verbal outcome in the language impaired profile. In conclusion, we provided a detailed description of how autistic preschoolers acquire language, and what factors might influence their trajectories. Our findings could inspire more personalized intervention for early autistic language difficulties.

Establishing the reliability of metrics extracted from long-form recordings using LENA and the ACLEW pipeline

Long-form audio recordings are increasingly used to study individual variation, group differences, and many other topics in theoretical and applied fields of developmental science, particularly for the description of children's language input (typically speech from adults) and children's language output (ranging from babble to sentences). The proprietary LENA software has been available for over a decade, and with it, users have come to rely on derived metrics like adult word count (AWC) and child vocalization counts (CVC), which have also more recently been derived using an open-source alternative, the ACLEW pipeline. Yet, there is relatively little work assessing the reliability of long-form metrics in terms of the stability of individual differences across time. Filling this gap, we analyzed eight spoken-language datasets: four from North American English-learning infants, and one each from British English-, French-, American English-/Spanish-, and Quechua-/Spanish-learning infants. The audio data were analyzed using two types of processing software: LENA and the ACLEW open-source pipeline. When all corpora were included, we found relatively low to moderate reliability (across multiple recordings, intraclass correlation coefficient attributed to the child identity [Child ICC], was < 50% for most metrics). There were few differences between the two pipelines. Exploratory analyses suggested some differences as a function of child age and corpora. These findings suggest that, while reliability is likely sufficient for various group-level analyses, caution is needed when using either LENA or ACLEW tools to study individual variation. We also encourage improvement of extant tools, specifically targeting accurate measurement of individual variation.

Factors affecting consonant production accuracy in children with cochlear implants: Expressive vocabulary and maternal education

BACKGROUND

Despite the ability of cochlear implants (CIs) to provide children with access to speech, there is considerable variability in spoken language outcomes. Research aimed at identifying factors influencing speech production accuracy is needed.

AIMS

To characterize the consonant production accuracy of children with cochlear implants (CWCI) and an age-matched group of children with typical hearing (CWTH) and to explore several factors that potentially affect the ability of both groups to accurately produce consonants.

METHODS & PROCEDURES

We administered the Bankson-Bernthal Test of Phonology (BBTOP) to a group of 25 CWCI (mean age = 4;9, SD = 1;6, range = 3;2-8;5) implanted prior to 30 months of age with a mean duration of implant usage of 3;6 and an age-matched group of 25 CWTH (mean age = 5;0, SD = 1;6, range = 3;1-8;6). The recorded results were transcribed, and the accuracy of the target consonants was determined. Expressive vocabulary size estimates were obtained from a language sample using the number of different words (NDW). A parent questionnaire provided information about maternal education, duration of CIs experience and other demographic characteristics of each child.

OUTCOMES & RESULTS

The CWCI group demonstrated some similarities to, and some differences from, their hearing peers. The CWCI demonstrated poorer consonant production accuracy overall and in various phonetic categories and word positions. However, both groups produced initial consonants more accurately than final consonants. Whilst CWCI had poorer production accuracy than CWTH for all phonetic categories (stops, nasals, fricatives, affricates, liquids and glides and consonant clusters), both groups exhibited similar error patterns across categories. For CWCI, the factors most related to consonant production accuracy when considered individually were expressive vocabulary size, followed by duration of CI experience, chronological age, maternal education and gender. The combination of maternal education and vocabulary size resulted in the best model of consonant production accuracy for this group. For the CWTH, chronological age followed by vocabulary size were most related to consonant production accuracy. No combination of factors yielded an improved model for the CWTH.

CONCLUSIONS & IMPLICATIONS

Whilst group differences in production accuracy between the CWCI and CWTH were found, the pattern of errors was similar for the two groups of children, suggesting that the children are at earlier stages of overall consonant production development. Although duration of CI experience was a significant covariate in a single-variable model of consonant production accuracy for CWCI, the best multivariate model of consonant production accuracy for these children was based on the combination of expressive vocabulary size and maternal education.

WHAT THIS PAPER ADDS

What is already known on the subject Research has shown that a range of factors is associated with consonant production accuracy by CWCIs, including factors such as the age at implant, duration of implant use, gender, other language skills and maternal education. Despite numerous studies that have examined speech sound production in these children, most have explored a limited number of factors that might explain the variability in scores obtained. Research that examines the potential role of a range of child-related and environmental factors in the same children is needed to determine the predictive role of these factors in speech production outcomes. What this paper adds to the existing knowledge Whilst the consonant production accuracy was lower for the CWCIs than for their typically hearing peers, there were some similarities suggesting that these children are experiencing similar, but delayed, acquisition of consonant production skills to that of their hearing peers. Whilst several factors are predictive of consonant production accuracy in children with implants, vocabulary diversity and maternal education, an indirect measure of socio-economic status, were the best combined predictors of consonant production accuracy. What are the potential or actual clinical implications of this work? Understanding the factors that shape individual differences in CWCI speech production is important for effective clinical decision-making and intervention planning. The present findings point to two potentially important factors related to speech sound production beyond the duration of robust hearing in CWCI, namely, a lexical diversity and maternal education. This suggests that intervention is likely most efficient that addresses both vocabulary development and speech sound development together. The current findings further suggest the importance of parental involvement and commitment to spoken language development and the importance of receiving early and consistent intervention aimed both at skill development and parental efficacy.

Caregivers as experimenters: Reducing unfamiliarity helps shy children learn words

Previous work has found that shy children show chance-level disambiguation and retention of novel word meanings in a typical lab-based word learning task. This effect could be explained in terms of shy children's aversion to unfamiliarity disrupting the requisite attentional processes, because the task is marked by a high degree of unfamiliarity. To test this argument, we examined whether increasing the familiarity of the task facilitates shy children's ability to form and retain word meanings. Two-year-old children (N = 23) took part in a word learning task in which their caregiver acted as the experimenter. On referent selection trials, children were presented with sets of three objects, one novel and two familiar, and were asked for either a familiar object using its known label, or a novel object using a novel word. Children were then tested on their retention of the previously formed novel word-object mappings. In this context of increased familiarity, shyness was unrelated to performance on referent selection trials. However, shyness was positively related to children's retention of the word-object mappings, meaning that shyer children outperformed less-shy children on this measure of word learning. These findings show that context-based familiarity interacts with intrinsic individual differences to affect word learning performance.

The effects of family, culture and sex on linguistic development across 20 languages

Languages vary in their complexity; caregivers vary in the way they structure their communicative interactions with children; and boys and girls can differ in their language skills. Using a multilevel modelling approach, we explored how these factors influence the path of language acquisition for young children growing up around the world (mean age 2-years 9-months; 56 girls). Across 43 different sites, we analysed 103 mother-child pairs who spoke 3,170,633 utterances, 16,209,659 morphemes, divided across 20 different languages: Afrikaans, Catalan, Cantonese, Danish, Dutch, English, Farsi, French, German, Hebrew, Icelandic, Irish, Italian, Japanese, Mandarin, Norwegian, Portuguese, Spanish, Swedish and Turkish. Using mean length of utterance (MLU) as a measure of language complexity and developmental skill, we found that variation in children's MLU was significantly explained by (a) between-language differences; namely the rate of child MLU growth was attuned to the complexity of their mother tongue, and (b) between-mother differences; namely mothers who used higher MLUs tended to have children with higher MLUs, regardless of which language they were learning and especially in the very young (<2.5 years-old). Controlling for family and language environment, we found no evidence of MLU sex differences in child speech nor in the speech addressed to boys and girls. By modelling language as a multilevel structure with cross-cultural variation, we were able to disentangle those factors that make children's pathway to language different and those that make it alike. RESEARCH HIGHLIGHTS: The speech of 103 mother-child pairs from 20 different languages showed large variation in the path of early language development. Language, family, but not the sex of the child, accounted for a significant proportion of individual differences in child speech, especially in the very young. The rate at which children learned language was attuned to the complexity of their mother tongue, with steeper trajectories for more complex language. Results demonstrate the relative influence of culture, family, and sex in shaping the path of language acquisition for different children.

Interactive roles of preterm-birth and socioeconomic status in cortical thickness of language-related brain structures: Findings from the Adolescent Brain Cognitive Development (ABCD) study

Preterm-born (PTB) children are at an elevated risk for neurocognitive difficulties in general and language difficulties more specifically. Environmental factors such as socio-economic status (SES) play a key role for Term children's language development. SES has been shown to predict PTB children's behavioral developmental trajectories, sometimes surpassing its role for Term children. However, the role of SES in the neurocognitive basis of PTB children's language development remains uncharted. Here, we aimed to evaluate the role of SES in the neural basis of PTB children's language performance. Leveraging the Adolescent Brain Cognitive Development (ABCD) Study, the largest longitudinal study of adolescent brain development and behavior to date, we showed that prematurity status (PTB versus Term) and multiple aspects of SES additively predict variability in cortical thickness, which is in turn related to children's receptive vocabulary performance. We did not find evidence to support the differential role of environmental factors for PTB versus Term children, underscoring that environmental factors are significant contributors to development of both Term and PTB children. Taken together, our results suggest that the environmental factors influencing language development might exhibit similarities across the full spectrum of gestational age.

Socioeconomic status, linguistic skills and language background differentially relate to preschoolers' emotional and behavioural profile

BACKGROUND

Proximal and distal factors interact to shape children's development and well-being. The present study aimed to examine socioeconomic status (SES), linguistic skills, and language background as concurrent predictors of socio-emotional and behavioural outcomes in heritage bilingual and monolingual children attending preschool.

METHODS

Parents of 1810 children (mean age = 63.42 months ± 7.36), attending preschool in Italy, completed the Four Factor Index of SES and the Strengths and Difficulties Questionnaire (SDQ). Teachers (n = 99) completed a questionnaire on children's linguistic skills and emotional and behavioural profiles. A subsample of 995 children was administered an expressive vocabulary task in Italian.

RESULTS

Regression analyses showed that linguistic skills were the only concurrent predictor of conduct problems, as well as the dominant predictor of hyperactivity/impulsivity, peer problems, and better prosocial behaviour. SES was negatively related to ADHD traits, peer problems, and prosocial behaviour. Finally, heritage bilingualism background was associated, although not as a primary predictor, with increased emotional problems, peer relationship problems, and lower teacher-rated emotional and behavioural skills. However, it was the main factor positively associated with prosocial behaviour.

CONCLUSIONS

The implications of these findings for research in this area and for educational policy are discussed, highlighting the need for a multidimensional perspective that includes linguistic skills and SES in the assessment of children's emotional and behavioural outcomes.

Supporting Early Language by Supporting Systemic Solutions

A large body of research shows connections between infants' and toddlers' home language input and a wide range of receptive and expressive early language skills. Some facets of caretaker input and early language skills are associated with socioeconomic status (SES), though not all. Given the complexity of language learning, language use, and its many pathways of connection to SES, testing causal links between these dimensions is difficult at best. Interventions aimed at changing parent language use have seen mixed success, in part because "language infusions" generally fail to target underlying challenges facing underresourced families, and perhaps because parent language is the wrong target. System-level interventions such as paid parental leave and expansion and enrichment of childcare and early education options hold greater promise for improving families' lives, with positive repercussions for a broad range of family and child outcomes, including linguistic ones.

Communication Skills in Toddlers Exposed to Maternal SARS-CoV-2 during Pregnancy

Studies about the effects of SARS-CoV-2 on pregnant women and children born to positive women are controversial with regard to possible inner ear-related damage but most of them do not detect the involvement of this virus in auditory function. However, only a few studies on long-term effects on language development are currently available because of the recent onset of the pandemic. The aim of this study was to investigate the impact of SARS-CoV-2 infection on perceptual and expressive abilities and the emerging development of communication in young children. To this purpose, the MacArthur-Bates Communicative Development Inventory-Words and Gestures form (CDI-WG), was administered to parents. In total, 115 children whose mother was infected by SARS-CoV-2 during pregnancy were enrolled in the study and evaluated at the Audiology Service of the Modena University Hospital. All children underwent Otoacoustic Emissions (OAE) at birth: 114/115 had a "pass" result bilaterally, while 1 case had a unilateral "refer" result. Overall, 110/115 newborns (95.65%) underwent audiological evaluation between 10-18 months of age. In 5/110 patients (3.6%), the Pure Tone Average (PTA) result was equal to 35 dB; one case had a hearing threshold of around 50 dB due to a bilateral effusive otitis media. A notable finding was the percentage of children with tubal dysfunction in both evaluations, within 2 months of age and around 12 months of age. Most children revealed normal hearing. The CDI-WG was completed by 56/115 families. The rate of children below the fifth percentile was 8.9% for sentences understood, 12.5% for words understood, and 5.4% for words produced. Concerning CDI-Gestures, only 2 children (3.6%) were below the fifth percentile. A structured audiological follow-up in association with the evaluation of communication skills of children appears fundamental, particularly in the years of maximum neuroplasticity. Long-term studies are still necessary to evaluate the possible consequences of the pandemic.

Comparison of speech and music input in North American infants' home environment over the first 2 years of life

Infants are immersed in a world of sounds from the moment their auditory system becomes functional, and experience with the auditory world shapes how their brain processes sounds in their environment. Across cultures, speech and music are two dominant auditory signals in infants' daily lives. Decades of research have repeatedly shown that both quantity and quality of speech input play critical roles in infant language development. Less is known about the music input infants receive in their environment. This study is the first to compare music input to speech input across infancy by analyzing a longitudinal dataset of daylong audio recordings collected in English-learning infants' home environments, at 6, 10, 14, 18, and 24 months of age. Using a crowdsourcing approach, 643 naïve listeners annotated 12,000 short snippets (10 s) randomly sampled from the recordings using Zooniverse, an online citizen-science platform. Results show that infants overall receive significantly more speech input than music input and the gap widens as the infants get older. At every age point, infants were exposed to more music from an electronic device than an in-person source; this pattern was reversed for speech. The percentage of input intended for infants remained the same over time for music while that percentage significantly increased for speech. We propose possible explanations for the limited music input compared to speech input observed in the present (North American) dataset and discuss future directions. We also discuss the opportunities and caveats in using a crowdsourcing approach to analyze large audio datasets. A video abstract of this article can be viewed at https://youtu.be/lFj_sEaBMN4 RESEARCH HIGHLIGHTS: This study is the first to compare music input to speech input in infants' natural home environment across infancy. We utilized a crowdsourcing approach to annotate a longitudinal dataset of daylong audio recordings collected in North American home environments. Our main results show that infants overall receive significantly more speech input than music input. This gap widens as the infants get older. Our results also showed that the music input was largely from electronic devices and not intended for the infants, a pattern opposite to speech input.

Socioeconomic status moderates associations between hippocampal development and cognition in preterms

OBJECTIVE

The hippocampus plays a critical role in cognitive networks. The anterior hippocampus is vulnerable to early-life stress and socioeconomic status (SES) with alterations persisting beyond childhood. How SES modifies the relationship between early hippocampal development and cognition remains poorly understood. This study examined associations between SES, structural and functional development of neonatal hippocampus, and 18-month cognition in very preterm neonates.

METHODS

In total, 179 preterm neonates were followed prospectively. Structural and resting-state functional MRI were obtained early-in-life and at term-equivalent age (median 32.9 and 41.1 weeks post-menstrual age) to calculate anterior and posterior hippocampal volumes and hippocampal functional connectivity strength. Eighteen-month cognition was assessed via Bayley-III. Longitudinal statistical analysis using generalized estimating equations, accounting for birth gestational age, post-menstrual age at scan, sex, and motion, was performed.

RESULTS

SES, measured as maternal education level, modified associations between anterior but not posterior hippocampal volumes and 18-month cognition (interaction term p = 0.005), and between hippocampal connectivity and cognition (interaction term p = 0.05). Greater anterior hippocampal volumes and hippocampal connectivity were associated with higher cognitive scores only in the lowest SES group. Maternal education alone did not predict neonatal hippocampal volume from early-in-life and term.

INTERPRETATION

SES modified the relationship between neonatal hippocampal development and 18-month cognition in very preterm neonates. The lack of direct association between maternal education and neonatal hippocampal volumes indicates that socio-environmental factors beyond the neonatal period contribute to modifying the relationship between hippocampal development and cognition. These findings point toward opportunities to more equitably promote optimal neurodevelopmental outcomes in very preterm infants.

An examination of measures of young children's interest in natural object categories

Developmental research utilizes various different methodologies and measures to study the cognitive development of young children; however, the reliability and validity of such measures have been a critical issue in all areas of research practices. To address this problem, particularly in the area of research on infants' interests, we examined the convergent validity of previously reported measures of children's interests in natural object categories, as indexed by (1) parents' estimation of their child's interest in the categories, (2) extrinsic (overt choices in a task), (3) intrinsic (looking time toward objects), and (4) physiological (pupil dilation) responses to objects of different categories. Additionally, we also examined the discriminant validity of all the aforementioned measures against the well-established and validated measure of parents' estimations of children's vocabulary knowledge. Children completed two tasks: (a) an eye-tracking task, where they were presented with images from a range of defined categories, which collected indices of looking time and pupillary activity; (b) a sticker-choice task, where they were asked to choose between two sticker-images from two different categories belonging to the range of categories assessed in the previous task. Parents completed two questionnaires to estimate (i) their child's interests and (ii) vocabulary knowledge in the categories presented. We first analyzed the discriminant validity between the two parent measures, and found a significant positive association between them. Our successive analyses showed no strong or significant associations between any of our measures, apart from a significant positive association between children's looking time and parents' estimations of children's vocabulary knowledge. From our findings, we conclude that measures of infants' interests thus far may not have sufficient reliability to adequately capture any potential relationship between these measures, or index different components of interest in young children. We suggest next steps for further validation studies in infant research.

Social Brain Perspectives on the Social and Evolutionary Neuroscience of Human Language

Human language and social cognition are two key disciplines that have traditionally been studied as separate domains. Nonetheless, an emerging view suggests an alternative perspective. Drawing on the theoretical underpinnings of the social brain hypothesis (thesis of the evolution of brain size and intelligence), the social complexity hypothesis (thesis of the evolution of communication), and empirical research from comparative animal behavior, human social behavior, language acquisition in children, social cognitive neuroscience, and the cognitive neuroscience of language, it is argued that social cognition and language are two significantly interconnected capacities of the human species. Here, evidence in support of this view reviews (1) recent developmental studies on language learning in infants and young children, pointing to the important crucial benefits associated with social stimulation for youngsters, including the quality and quantity of incoming linguistic information, dyadic infant/child-to-parent non-verbal and verbal interactions, and other important social cues integral for facilitating language learning and social bonding; (2) studies of the adult human brain, suggesting a high degree of specialization for sociolinguistic information processing, memory retrieval, and comprehension, suggesting that the function of these neural areas may connect social cognition with language and social bonding; (3) developmental deficits in language and social cognition, including autism spectrum disorder (ASD), illustrating a unique developmental profile, further linking language, social cognition, and social bonding; and (4) neural biomarkers that may help to identify early developmental disorders of language and social cognition. In effect, the social brain and social complexity hypotheses may jointly help to describe how neurotypical children and adults acquire language, why autistic children and adults exhibit simultaneous deficits in language and social cognition, and why nonhuman primates and other organisms with significant computational capacities cannot learn language. But perhaps most critically, the following article argues that this and related research will allow scientists to generate a holistic profile and deeper understanding of the healthy adult social brain while developing more innovative and effective diagnoses, prognoses, and treatments for maladies and deficits also associated with the social brain.