Using language input and lexical processing to predict vocabulary size

A brief tablet-based intervention benefits linguistic and communicative abilities in toddlers and preschoolers

Young children's linguistic and communicative abilities are foundational for their academic achievement and overall well-being. We present the positive outcomes of a brief tablet-based intervention aimed at teaching toddlers and preschoolers new word-object and letter-sound associations. We conducted two experiments, one involving toddlers ( ~ 24 months old, n = 101) and the other with preschoolers ( ~ 42 months old, n = 152). Using a pre-post equivalent group design, we measured the children's improvements in language and communication skills resulting from the intervention. Our results showed that the intervention benefited toddlers' verbal communication and preschoolers' speech comprehension. Additionally, it encouraged vocalizations in preschoolers and enhanced long-term memory for the associations taught in the study for all participants. In summary, our study demonstrates that the use of a ludic tablet-based intervention for teaching new vocabulary and pre-reading skills can improve young children's linguistic and communicative abilities, which are essential for future development.

Developmental change in English-learning children's interpretations of salient pitch contours in word learning

To efficiently recognize words, children learning an intonational language like English should avoid interpreting pitch-contour variation as signaling lexical contrast, despite the relevance of pitch at other levels of structure. Thus far, the developmental time-course with which English-learning children rule out pitch as a contrastive feature has been incompletely characterized. Prior studies have tested diverse lexical contrasts and have not tested beyond 30 months. To specify the developmental trajectory over a broader age range, we extended a prior study (Quam & Swingley, 2010), in which 30-month-olds and adults disregarded pitch changes, but attended to vowel changes, in newly learned words. Using the same phonological contrasts, we tested 3- to 5-year-olds, 24-month-olds, and 18-month-olds. The older two groups were tested using the language-guided-looking method. The oldest group attended to vowels but not pitch. Surprisingly, 24-month-olds ignored not just pitch but sometimes vowels as well-conflicting with prior findings of phonological constraint at 24 months. The youngest group was tested using the Switch habituation method, half with additional phonetic variability in training. Eighteen-month-olds learned both pitch-contrasted and vowel-contrasted words, whether or not additional variability was present. Thus, native-language phonological constraint was not evidenced prior to 30 months (Quam & Swingley, 2010). We contextualize our findings within other recent work in this area.

Early childhood education language environments: considerations for research and practice

The importance of developing early language and literacy skills is acknowledged by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) as a global human rights issue. Indeed, research suggests that language abilities are foundational for a host of cognitive, behavioral, and social-emotional outcomes. Therefore, it is critical to provide experiences that foster language acquisition across early learning settings. Central to these efforts is incorporating assessments of language environments into research and practice to drive quality improvement. Yet, several barriers may be preventing language environment assessments from becoming widely integrated into early education. In this brief, we review evidence on the types of experiences that promote language development, describe characteristics of language environment assessments, and outline practical and philosophical considerations to assist with decision-making. Further, we offer recommendations for future research that may contribute knowledge regarding strategies to assess and support language development. In addressing both areas, we highlight the potential for early childhood language environments to advance equity.

Does the public know what researchers know? Perceived task difficulty impacts adults' intuitions about children's early word learning

The present study examined adults' understanding of children's early word learning. Undergraduates, non-parents, parents, and Speech-Language Pathologists (N = 535, 74% female, 56% White) completed a survey with 11 word learning principles from the perspective of a preschooler. Questions tested key principles from early word learning research. For each question, participants were prompted to select an answer based on the perspective of a preschooler. Adults demonstrated aligned intuitions for all principles except those derived from domain-general theories, regardless of experience with language development (Experiment 1). Experiment 2 revealed that perceived difficulty of a task for a preschooler impacted adults' reasoning about word learning processes. Experiment 3 ruled out level of confidence and interest as mechanisms to explain the results. These results highlight disconnects in knowledge between the cognitive development research community and the general public. Therefore, efforts must be made to communicate scientific findings to the broader non-academic community, emphasizing children's ability to excel at word learning in the face of task difficulty.

Caregiver linguistic alignment to autistic and typically developing children: A natural language processing approach illuminates the interactive components of language development

BACKGROUND

Language development is a highly interactive activity. However, most research on linguistic environment has focused on the quantity and complexity of linguistic input to children, with current models showing that complexity facilitates language in both typically developing (TD) and autistic children.

AIMS

After reviewing existing work on caregiver engagement of children's utterances, we aim to operationalize such engagement with automated measures of linguistic alignment, thereby providing scalable tools to assess caregivers' active reuse of their children's language. By assessing the presence of alignment, its sensitivity to the child's individual differences and how well it predicts language development beyond current models across the two groups, we showcase the usefulness of the approach and provide initial empirical foundations for further conceptual and empirical investigations.

METHODS

We measure lexical, syntactic and semantic types of caregiver alignment in a longitudinal corpus involving 32 adult-autistic child and 35 adult-TD child dyads, with children between 2 and 5 years of age. We assess the extent to which caregivers repeat their children's words, syntax, and semantics, and whether these repetitions predict language development beyond more standard predictors.

RESULTS

Caregivers tend to re-use their child's language in a way that is related to the child's individual, primarily linguistic, differences. Caregivers' alignment provides unique information improving our ability to predict future language development in both typical and autistic children.

CONCLUSIONS

We provide evidence that language development also relies on interactive conversational processes, previously understudied. We share carefully detailed methods, and open-source scripts so as to systematically extend our approach to new contexts and languages.

From Recognizing Known Words to Learning New Ones: Comparing Online Speech Processing in Typically Developing and Late-Talking 2-Year-Olds

PURPOSE

This study examines online speech processing in typically developing and late-talking 2-year-old children, comparing both groups' word recognition, word prediction, and word learning.

METHOD

English-acquiring U.S. children, from the "When to Worry" study of language and social-emotional development, were identified as typical talkers (n = 67, M age = 27.0 months, SD = 1.4; Study 1) or late talkers (n = 30, M age = 27.0 months, SD = 2.0; Study 2). Children completed an eye-tracking task assessing their ability to recognize both nouns and verbs, to use verbs to predict an upcoming noun's referent, and to use verbs to infer the meaning of novel nouns.

RESULTS

Both typical and late talkers recognized nouns and verbs and used familiar verbs to predict the referents of upcoming nouns, whether the noun was familiar ("You can eat the apple") or novel ("You can eat the dax"). Late talkers were slower in using familiar nouns to orient to the target and were both slower and less accurate in using familiar verbs to identify the upcoming noun's referent. Notably, however, both groups learned and retained novel word meanings with similar success.

CONCLUSIONS

Late talkers demonstrated slower lexical processing, especially for verbs. Yet, their success in using familiar verbs to learn novel nouns suggests that, as a group, their slower processing did not impair word learning in this task. This sets the foundation for future work investigating whether these measures predict later language outcomes and can differentiate late talkers with transient delays from those with language disorders.

Reading Comprehension of Chinese-Speaking Children With Hearing Loss: The Roles of Metalinguistic Awareness and Vocabulary Knowledge

PURPOSE

This study aims to explore the contributions of phonological awareness (PA) and morphological awareness (MA) to the reading comprehension skills of Chinese-speaking children with hearing loss (HL) and examine the possible mediation effect of vocabulary knowledge on the relationships of PA and MA with their reading comprehension.

METHOD

The participants were 28 Chinese-speaking children with HL, who were followed from Grade 1 through Grade 2. They were administered a series of tests that measured their PA and MA at the beginning of Grade 1, vocabulary knowledge at the end of Grade 1, and reading comprehension at the end of Grade 2.

RESULTS

MA significantly accounted for additional variance in reading comprehension beyond the effect of PA but not vice versa. Both PA and MA contributed uniquely to vocabulary knowledge, which completely mediated the relationships of PA and MA with reading comprehension.

CONCLUSIONS

PA and MA are both essential to the development of vocabulary knowledge and reading comprehension in Chinese-speaking children with HL; however, MA seems to be more important than PA in their reading comprehension. PA and MA significantly affect children's reading comprehension through their influence on vocabulary knowledge. This study has replicated previous evidence on the importance of PA, MA, and vocabulary knowledge in the reading comprehension of children with typical hearing, and has extended its significance to children with HL. In addition, the findings have the potential to inform educational practitioners regarding the importance of teaching essential reading skills to Chinese-speaking children with HL.

Improving Children's Expressive Language and Auditory Comprehension Through Responsive Caregiving: Evidence from a Randomized Controlled Trial of a Strength-Based Video-Coaching Intervention

Young children from low-SES backgrounds are at higher risk for delayed language development, likely due to differences in their home language environment and decreased opportunities for back and forth communicative exchange. Intervention strategies that encourage reciprocal caregiver-child interactions may effectively promote young children's language development and enhance optimal language outcomes. The Filming Interactions to Nurture Development (FIND) program is a brief strength-based video-coaching intervention designed to promote increased back and forth ("serve and return") interactions between caregivers and their children. The current study used data from a randomized controlled trial (RCT) to examine the effectiveness of the FIND program in improving auditory comprehension and expressive communication skills among children from low-SES backgrounds. The current study used a pretest-posttest design to evaluate intervention effects from an RCT with 91 low-SES families. Families with children aged 4 to 36 months old (41.8% female) were randomly assigned to an active control or FIND intervention group. Children's auditory comprehension and expressive communication were assessed using the Preschool Language Scales, Fifth Edition (PLS-5) during both pre- and post-intervention sessions. Children in the FIND intervention group showed significantly increased expressive communication skills and a non-significant increase in auditory comprehension skills across the intervention period. In contrast, children in the active control group showed non-significant changes in expressive communication and a statistically significant decline in auditory comprehension abilities between pre- and post-intervention assessments. All analyses controlled for sex, age, and home language. This study provides preliminary evidence that the FIND intervention promotes the development of expressive and receptive language skills among young children in high-stress, low-SES environments.

Drivers of Lexical Processing and Implications for Early Learning

Understanding words in unfolding speech requires the coordination of many skills to support successful and rapid comprehension of word meanings. This multifaceted ability emerges before our first birthday, matures over a protracted period of development, varies widely between individuals, forecasts future learning outcomes, and is influenced by immediate context, prior knowledge, and lifetime experience. This article highlights drivers of early lexical processing abilities while exploring questions regarding how learners begin to acquire, represent, and activate meaning in language. The review additionally explores how lexical processing and representation are connected while reflecting on how network science approaches can support richly detailed insights into this connection in young learners. Future research avenues are considered that focus on addressing how language processing and other cognitive skills are connected.

LANGUAGE EXPOSURE PREDICTS CHILDREN'S PHONETIC PATTERNING: EVIDENCE FROM LANGUAGE SHIFT

Although understanding the role of the environment is central to language acquisition theory, rarely has this been studied for children's phonetic development, and receptive and expressive language experiences in the environment are not distinguished. This last distinction may be crucial for child speech production in particular, because production requires coordination of low-level speech-motor planning with high-level linguistic knowledge. In this study, the role of the environment is evaluated in a novel way-by studying phonetic development in a bilingual community undergoing rapid language shift. This sociolinguistic context provides a naturalistic gradient of the amount of children's exposure to two languages and the ratio of expressive to receptive experiences. A large-scale child language corpus encompassing over 500 hours of naturalistic South Bolivian Quechua and Spanish speech was efficiently annotated for children's and their caregivers' bilingual language use. These estimates were correlated with children's patterns in a series of speech production tasks. The role of the environment varied by outcome: children's expressive language experience best predicted their performance on a coarticulation-morphology measure, while their receptive experience predicted performance on a lower-level measure of vowel variability. Overall these bilingual exposure effects suggest a pathway for children's role in language change whereby language shift can result in different learning outcomes within a single speech community. Appropriate ways to model language exposure in development are discussed.

Assessment of Communication Abilities in Four Children with Early Bilateral CIs in Clinical and Home Environments with LENA System: A Case Report

Children’s language acquisition is underpinned by the quantity and quality of linguistic stimulation. Early diagnosis and cochlear implantation (CI), along with a family-centered intervention, are regarded as critical factors in providing appropriate language stimulation and thus supporting successful language outcomes in children with sensory neural hearing loss (SNHL). Considering the lack of tools to assess early language skills and open issues regarding the early predictors of CI outcomes, our goal was to evaluate the potential usability of the Language ENvironment Analysis (LENA) system as an early assessment and/or predictive tool. Clinical video recordings, LENA home recordings, and vocabulary scores were used to assess the progression of communication abilities of four children with CIs (6–35 m.o.). The data revealed a positive correlation between the estimated mean length of utterance (EMLU), vocal conversational turns (CT) in clinical video recordings, and receptive vocabulary, as well as the CT count in LENA being a significant predictor of productive vocabulary. These findings lead us to conclude that the LENA system has the potential to be used as an additional (tele-)measure in the early assessment of communication abilities of children with CI, as well as as a tool in the research of early predictors of CI outcomes.

Lexico-semantic structure in vocabulary and its links to lexical processing in toddlerhood and language outcomes at age three

Toddlerhood is marked by advances in several lexico-semantic skills, including improvements in the size and structure of the lexicon and increased efficiency in lexical processing. This project seeks to delineate how early changes in vocabulary size and vocabulary structure support lexical processing (Experiment 1), and how these three skills together (vocabulary size, structure, and lexical processing) relate to later language outcomes at age 3 (Experiment 2). Experiment 1 explored how the size and semantic structure of toddlers' vocabulary from 18 to 24 months (N = 61) predicted performance on two lexical processing tasks (semantically related and semantically unrelated trials). Denser semantic connectivity (i.e., global level connectivity between near and far neighbors) positively associated with semantic interference during semantically related lexical processing, whereas denser category structure (i.e., lower-level connectivity between near neighbors) facilitated lexical processing in semantically unrelated trials. In Experiment 2, a subset of the same children (N = 49) returned at age 36 months and completed a comprehensive assessment of their language skills using the Clinical Evaluation of Language Fundamental, Preschool 2 (CELF-P2). Here, earlier measures of lexico-semantic connectivity and lexical processing best predicted age 3 language skill. The findings support accounts that early vocabulary structure and lexical processing skills promote continued growth in language. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Prior Exposure and Toddlers' Sleep-Related Memory for Novel Words

Children can easily link a novel word to a novel, unnamed object—something referred to as fast mapping. Despite the ease and speed with which children do this, their memories for novel fast-mapped words can be poor unless they receive memory supports such as further exposure to the words or sleep. Axelsson, Swinton, Winiger, and Horst (2018) found that 2.5-year-old children who napped after fast mapping had better retention of novel words than children who did not nap. Retention declined for those who did not nap. The children received no memory supports and determined the word-object mappings independently. Previous studies report enhanced memories after sleeping in children and adults, but the napping children’s retention in the Axelsson et al. study remained steady across time. We report a follow-up investigation where memory supports are provided after fast mapping to test whether memories would be enhanced following napping. Children’s retention of novel words improved and remained greater than chance; however, there was no nap effect with no significant difference between the children who napped and those who did not. These findings suggest that when memory supports are provided, retention improves, and the word–object mappings remain stable over time. When memory traces are weak and labile, such as after fast mapping, without further memory supports, sleeping soon after helps stabilise and prevent decay of word–object mappings.

Efficient Estimation of Children's Language Exposure in Two Bilingual Communities

Purpose The language that children hear early in life is associated with their speech-language outcomes. This line of research relies on naturalistic observations of children's language input, often captured with daylong audio recordings. However, the large quantity of data that daylong recordings generate requires novel analytical tools to feasibly parse thousands of hours of naturalistic speech. This study outlines a new approach to efficiently process and sample from daylong audio recordings made in two bilingual communities, Spanish-English in the United States and Quechua-Spanish in Bolivia, to derive estimates of children's language exposure. Method We employed a general sampling with replacement technique to efficiently estimate two key elements of children's early language environments: (a) proportion of child-directed speech (CDS) and (b) dual language exposure. Proportions estimated from random sampling of 30-s segments were compared to those from annotations over the entire daylong recording (every other segment), as well as parental report of dual language exposure. Results Results showed that approximately 49 min from each recording or just 7% of the overall recording was required to reach a stable proportion of CDS and bilingual exposure. In both speech communities, strong correlations were found between bilingual language estimates made using random sampling and all-day annotation techniques. A strong association was additionally found for CDS estimates in the United States, but this was weaker at the Bolivian site, where CDS was less frequent. Dual language estimates from the audio recordings did not correspond well to estimates derived from parental report collected months apart. Conclusions Daylong recordings offer tremendous insight into children's daily language experiences, but they will not become widely used in developmental research until data processing and annotation time substantially decrease. We show that annotation based on random sampling is a promising approach to efficiently estimate ambient characteristics from daylong recordings that cannot currently be estimated via automated methods.

The Starting Big approach to language learning

The study of language acquisition has a long and contentious history: researchers disagree on what drives this process, the relevant data, and the interesting questions. Here, I outline the Starting Big approach to language learning, which emphasizes the role of multiword units in language, and of coarse-to-fine processes in learning. I outline core predictions and supporting evidence. In short, the approach argues that multiword units are integral building blocks in language; that such units can facilitate mastery of semantically opaque relations between words; and that adults rely on them less than children, which can explain (some of) their difficulty in learning a second language. The Starting Big approach is a theory of how children learn language, how language is represented, and how to explain differences between first and second language learning. I discuss the learning and processing models at the heart of the approach and their cross-linguistic implications.

Practice and experience predict coarticulation in child speech

Much research in child speech development suggests that young children coarticulate more than adults. There are multiple, not mutually-exclusive, explanations for this pattern. For example, children may coarticulate more because they are limited by immature motor control. Or they may coarticulate more if they initially represent phonological segments in larger, more holistic units such as syllables or feet. We tested the importance of several different explanations for coarticulation in child speech by evaluating how four-year-olds' language experience, speech practice, and speech planning predicted their coarticulation between adjacent segments in real words and paired nonwords. Children with larger vocabularies coarticulated less, especially in real words, though there were no reliable coarticulatory differences between real words and nonwords after controlling for word duration. Children who vocalized more throughout a daylong audio recording also coarticulated less. Quantity of child vocalizations was more predictive of the degree of children's coarticulation than a measure of receptive language experience, adult word count. Overall, these results suggest strong roles for children's phonological representations and speech practice, as well as their immature fine motor control, for coarticulatory development.

Lexical processing of nouns and verbs at 36 months of age predicts concurrent and later vocabulary and school readiness

Children's lexical processing speed at 18 to 25 months of age has been linked to concurrent and later language abilities. In the current study, we extend this finding to children aged 36 months. Children (N = 126) participated in a lexical processing task in which they viewed two static images on noun trials (e.g., an ear of corn and a hat), or two dynamic video clips on verb trials (e.g., a woman stretching and the same woman clapping), and heard an auditory prompt labeling one of them (e.g., "Where is she stretching?"). They also participated in standard assessments of language and school readiness. The results indicated that lexical processing speed (i.e., how long they required to look to the labeled image or scene) was associated with measures of concurrent receptive vocabulary, as well as receptive vocabulary and school readiness two years later, although the associations are weaker than for younger children.

Two-year-old children's processing of two-word sequences occurring 19 or more times per million and their influence on subsequent word learning

We know that 8-month-old infants track the statistical properties of a series of syllables and that 2- and 3-year-old children process familiar phrases more efficiently than unfamiliar phrases, but less is known about the intermediary level of two-word sequences. In Study 1, 2-year-olds (N = 45, mean age = 651 days) heard two-word sequences consisting of a prime word followed by a noun, with two pictures appearing on the screen (depicting the noun and a distractor). Eye tracking showed that children looked more quickly at the noun picture for two-word sequences occurring an average of 19 times per million and 206 times per million in child-directed speech than for novel sequences. In Study 2, corpus analyses showed that 2-year-olds' noun learning increased in line with the frequency of the two-word sequence that preceded it in caregiver speech utterances. This effect holds even after controlling nouns for frequency in caregiver speech, phonemic length, neighborhood density, phonotactic probability, and concreteness and after removing nouns produced in isolation by caregivers and nouns produced by children before being produced by caregivers. These studies show that young children's language processing is facilitated by known two-word sequences, allowing children to focus on more novel aspects of the utterance. Such efficiencies are far-reaching because nearly two thirds of child-directed utterances contain two-word sequences with frequencies of 19 or more per million.

A meta-analysis of the predictability of LENA™ automated measures for child language development

Early language environment plays a critical role in child language development. The Language ENvironment Analysis (LENA™) system allows researchers and clinicians to collect daylong recordings and obtain automated measures to characterize a child's language environment. This meta-analysis evaluates the predictability of LENA's automated measures for language skills in young children. We systematically searched reports for associations between LENA's automated measures, specifically, adult word count (AWC), conversational turn count (CTC), and child vocalization count (CVC), and language skills in children younger than 48 months. Using robust variance estimation, we calculated weighted mean effect sizes and conducted moderator analyses exploring the factors that might affect this relationship. The results revealed an overall medium effect size for the correlation between LENA's automated measures and language skills. This relationship was largely consistent regardless of child developmental status, publication status, language assessment modality and method, or the age at which the LENA recording was taken; however, the effect was weakly moderated by the gap between LENA recordings and language measures taken. Among the three measures, there were medium associations between CTC and CVC and language, whereas there was a small-to-medium association between AWC and language. These findings extend beyond validation work conducted by the LENA Research Foundation and suggest certain predictive strength of LENA's automated measures for child language. We discussed possible mechanisms underlying the observed associations, as well as the theoretical, methodological, and clinical implications of these findings.

Parental Language Input to Children With Hearing Loss: Does It Matter in the End?

Purpose Parental language input (PLI) has reliably been found to influence child language development for children at risk of language delay, but previous work has generally restricted observations to the preschool years. The current study examined whether PLI during the early years explains variability in the spoken language abilities of children with hearing loss at those young ages, as well as later in childhood. Participants One hundred children participated: 34 with normal hearing, 24 with moderate losses who used hearing aids (HAs), and 42 with severe-to-profound losses who used cochlear implants (CIs). Mean socioeconomic status was middle class for all groups. Children with CIs generally received them early. Method Samples of parent-child interactions were analyzed to characterize PLI during the preschool years. Child language abilities (CLAs) were assessed at 48 months and 10 years of age. Results No differences were observed across groups in how parents interacted with their children. Nonetheless, strong differences across groups were observed in the effects of PLI on CLAs at 48 months of age: Children with normal hearing were largely resilient to their parents' language styles. Children with HAs were most influenced by the amount of PLI. Children with CIs were most influenced by PLI that evoked child language and modeled more complex versions. When potential influences of preschool PLI on CLAs at 10 years of age were examined, those effects at preschool were replicated. When mediation analyses were performed, however, it was found that the influences of preschool PLI on CLAs at 10 years of age were partially mediated by CLAs at preschool. Conclusion PLI is critical to the long-term spoken language abilities of children with hearing loss, but the style of input that is most effective varies depending on the severity of risk for delay.

Infant language predicts fathers' vocabulary in infant-directed speech

Research on sources of individual difference in parental Infant-Directed Speech (IDS) is limited and there is a particular lack of research on fathers' compared to mothers' speech. This study examined the predictive relations between infant characteristics and variability in paternal lexical diversity (LD) in dyadic free play with two-year-olds (M = 24.1 months, SD = 1.39, 35 girls). Ten minutes of interaction for sixty-four father-infant dyads were transcribed and multiple regression analyses were performed to examine the effects of a set of distal and proximal sources of infant influence on paternal LD. Fathers' LD was predicted only by infant language, both standardised language scores and dynamic language measures, and was not predicted by infant age, gender, executive function, or temperament. Findings are discussed in the light of the complex interplay of factors contributing to variability in IDS and the infant's linguistic environment.

Early language exposure supports later language skills in infants with and without autism

The way that parents communicate with their typically developing infants is associated with later infant language development. Here we aim to show that these associations are observed in infants subsequently diagnosed with autism spectrum disorder (ASD). This study had three groups: high-familial-risk infants who did not have ASD (n = 46); high-familial-risk infants who had ASD (n = 14); and low-familial-risk infants who exhibited typical development (n = 36). All-day home language recordings were collected at 9 and 15 months, and language skills were assessed at 24 months. Across all infants in the study, including those with ASD, a richer home language environment (e.g., hearing more adult words and experiencing more conversational turns) at 9 and 15 months was associated with better language skills. Higher parental educational attainment was associated with a richer home language environment. Mediation analyses showed that the effect of education on child language skills was explained by the richness of the home language environment. Exploratory analyses revealed that typically developing infants experience an increase in caregiver-child conversational turns across 9-15 months, a pattern not seen in children with ASD. The current study shows that parent behavior during the earliest stages of life can have a significant impact on later development, highlighting the home language environment as means to support development in infants with ASD. Autism Res 2019, 12: 1784-1795. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: It has long been understood that caregiver speech supports language skills in typically developing infants. In this study, parents of infants who were later diagnosed with ASD and parents of infants in the control groups completed all-day home language recordings. We found that for all infants in our study, those who heard more caregiver speech had better language skills later in life. Parental education level was also related to how much caregiver speech an infant experienced.

Hearing me hearing you: Reciprocal effects between child and parent language in autism and typical development

Language development in typically developing children (TD) has traditionally been investigated in relation to environmental factors, while language in children with autism spectrum disorder (ASD) has primarily been related to child-based factors. We employ a longitudinal corpus of 32 preschoolers with ASD and 35 linguistically matched TD peers recorded over 6 visits (ranging between 2 and 5 years of age) to investigate the relative importance of child-based and environmental factors in language development for both populations. We also investigate the reciprocal interaction between children's response to parents' input, and parents' response to children's production. We report six major findings. (1) Children's production of word types, tokens, and MLU increased across visits, and were predicted by their Expressive Language (EL) (positively) and diagnosis (negatively) from Visit 1. (2) Parents' production also increased across visits, and was predicted by their child's nonverbal cognition (positively) and diagnosis (negatively) from Visit 1. (3) At all visits and across groups, children and parents matched each other in lexical and syntactic production; (4) Parents who produced longer MLUs during a given visit had children who produced more word types and tokens, and had longer MLUs, at the subsequent visit. (5) When both child EL at Visit 1 and parent MLU were included in the model, both contributed significantly to future child language; however, EL accounted for a greater proportion of the variance. (6) Finally, children's speech significantly predicted parent speech at the next visit. Taken together, these results draw more attention to the importance of child-based factors in the early language development of TD children, and to the importance of parental language factors in the early language development of children with ASD.