Look who's talking: speech style and social context in language input to infants are linked to concurrent and future speech development

Does narrator variability facilitate incidental word learning in the classroom?

Recent studies have revealed that presenting novel words across various contexts (i.e., contextual diversity) helps to consolidate the meaning of these words both in adults and children. This effect has been typically explained in terms of semantic distinctiveness (e.g., Semantic Distinctiveness Model, Jones et al., Canadian Journal of Experimental Psychology, 66(2), 115, 2012). However, the relative influence of other, non-semantic, elements of the context is still unclear. In this study, we examined whether incidental learning of new words in children was facilitated when the words were uttered by several individuals rather than when they were uttered by the same individual. In the learning phase, the to-be-learned words were presented through audible fables recorded either by the same voice (low diversity) or by different voices (high diversity). Subsequently, word learning was assessed through two orthographic and semantic integration tasks. Results showed that words uttered by different voices were learned better than those uttered by the same voice. Thus, the benefits of contextual diversity in word learning extend beyond semantic differences among contexts; they also benefit from perceptual differences among contexts.

Vocal development in a large-scale crosslinguistic corpus

This study evaluates whether early vocalizations develop in similar ways in children across diverse cultural contexts. We analyze data from daylong audio recordings of 49 children (1-36 months) from five different language/cultural backgrounds. Citizen scientists annotated these recordings to determine if child vocalizations contained canonical transitions or not (e.g., "ba" vs. "ee"). Results revealed that the proportion of clips reported to contain canonical transitions increased with age. Furthermore, this proportion exceeded 0.15 by around 7 months, replicating and extending previous findings on canonical vocalization development but using data from the natural environments of a culturally and linguistically diverse sample. This work explores how crowdsourcing can be used to annotate corpora, helping establish developmental milestones relevant to multiple languages and cultures. Lower inter-annotator reliability on the crowdsourcing platform, relative to more traditional in-lab expert annotators, means that a larger number of unique annotators and/or annotations are required, and that crowdsourcing may not be a suitable method for more fine-grained annotation decisions. Audio clips used for this project are compiled into a large-scale infant vocalization corpus that is available for other researchers to use in future work.

Relationship Between Parent Vowel Hyperarticulation in Infant-Directed Speech and Infant Phonetic Complexity on the Level of Conversational Turns

When speaking to infants, parents typically use infant-directed speech, a speech register that in several aspects differs from that directed to adults. Vowel hyperarticulation, that is, extreme articulation of vowels, is one characteristic sometimes found in infant-directed speech, and it has been suggested that there exists a relationship between how much vowel hyperarticulation parents use when speaking to their infant and infant language development. In this study, the relationship between parent vowel hyperarticulation and phonetic complexity of infant vocalizations is investigated. Previous research has shown that on the level of subject means, a positive correlational relationship exists. However, the previous findings do not provide information about the directionality of that relationship. In this study the relationship is investigated on a conversational turn level, which makes it possible to draw conclusions on whether the behavior of the infant is impacting the parent, the behavior of the parent is impacting the infant, or both. Parent vowel hyperarticulation was quantified using the vhh-index, a measure that allows vowel hyperarticulation to be estimated for individual vowel tokens. Phonetic complexity of infant vocalizations was calculated using the Word Complexity Measure for Swedish. Findings were unexpected in that a negative relationship was found between parent vowel hyperarticulation and phonetic complexity of the immediately following infant vocalization. Directionality was suggested by the fact that no such relationship was found between infant phonetic complexity and vowel hyperarticulation of the immediately following parent utterance. A potential explanation for these results is that high degrees of vowel hyperarticulation either provide, or co-occur with, large amounts of phonetic and/or linguistic information, which may occupy processing resources to an extent that affects production of the next vocalization.

How Chatty Are Daddies? An Exploratory Study of Infants' Language Environments

Purpose Fathers play a critical but underresearched role in their children's cognitive and linguistic development. Focusing on two-parent families with a mother and a father, the present longitudinal study explores the amount of paternal input infants hear during the first 2 years of life, how this input changes over time, and how it relates to child volubility. We devote special attention to parentese, a near-universal style of infant-directed speech, distinguished by its higher pitch, slower tempo, and exaggerated intonation. Method We examined the daylong recordings of the same 23 infants at ages 6, 10, 14, 18, and 24 months, given English-speaking families. The infants were recorded in the presence of their parents (mother-father dyads), who were predominantly White and ranged from mid to high socioeconomic status (SES). We analyzed the effects of parent gender and child age on adult word counts and parentese, as well as the effects of maternal and paternal word counts and parentese on child vocalizations. Results On average, the infants were exposed to 46.8% fewer words and 51.9% less parentese from fathers than from mothers, even though paternal parentese grew at a 2.8-times faster rate as the infants aged. An asymmetry emerged where maternal word counts and paternal parentese predicted child vocalizations, but paternal word counts and maternal parentese did not. Conclusions While infants may hear less input from their fathers than their mothers in predominantly White, mid-to-high SES, English-speaking households, paternal parentese still plays a unique role in their linguistic development. Future research on sources of variability in child language outcomes should thus control for parental differences since parents' language can differ substantially and differentially predict child language.

An Association Between Phonetic Complexity of Infant Vocalizations and Parent Vowel Hyperarticulation

Extreme or exaggerated articulation of vowels, or vowel hyperarticulation, is a characteristic commonly found in infant-directed speech (IDS). High degrees of vowel hyperarticulation in parent IDS has been tied to better speech sound category development and bigger vocabulary size in infants. In the present study, the relationship between vowel hyperarticulation in Swedish IDS to 12-month-old and phonetic complexity of infant vocalizations is investigated. Articulatory adaptation toward hyperarticulation is quantified as difference in vowel space area between IDS and adult-directed speech (ADS). Phonetic complexity is estimated using the Word Complexity Measure for Swedish (WCM-SE). The results show that vowels in IDS was more hyperarticulated than vowels in ADS, and that parents' articulatory adaptation in terms of hyperarticulation correlates with phonetic complexity of infant vocalizations. This can be explained either by the parents' articulatory behavior impacting the infants' vocalization behavior, the infants' social and communicative cues eliciting hyperarticulation in the parents' speech, or the two variables being impacted by a third, underlying variable such as parents' general communicative adaptiveness.

Early language experience in a Papuan community

The rate at which young children are directly spoken to varies due to many factors, including (a) caregiver ideas about children as conversational partners and (b) the organization of everyday life. Prior work suggests cross-cultural variation in rates of child-directed speech is due to the former factor, but has been fraught with confounds in comparing postindustrial and subsistence farming communities. We investigate the daylong language environments of children (0;0-3;0) on Rossel Island, Papua New Guinea, a small-scale traditional community where prior ethnographic study demonstrated contingency-seeking child interaction styles. In fact, children were infrequently directly addressed and linguistic input rate was primarily affected by situational factors, though children's vocalization maturity showed no developmental delay. We compare the input characteristics between this community and a Tseltal Mayan one in which near-parallel methods produced comparable results, then briefly discuss the models and mechanisms for learning best supported by our findings.

ALICE: An open-source tool for automatic measurement of phoneme, syllable, and word counts from child-centered daylong recordings

Recordings captured by wearable microphones are a standard method for investigating young children's language environments. A key measure to quantify from such data is the amount of speech present in children's home environments. To this end, the LENA recorder and software-a popular system for measuring linguistic input-estimates the number of adult words that children may hear over the course of a recording. However, word count estimation is challenging to do in a language- independent manner; the relationship between observable acoustic patterns and language-specific lexical entities is far from uniform across human languages. In this paper, we ask whether some alternative linguistic units, namely phone(me)s or syllables, could be measured instead of, or in parallel with, words in order to achieve improved cross-linguistic applicability and comparability of an automated system for measuring child language input. We discuss the advantages and disadvantages of measuring different units from theoretical and technical points of view. We also investigate the practical applicability of measuring such units using a novel system called Automatic LInguistic unit Count Estimator (ALICE) together with audio from seven child-centered daylong audio corpora from diverse cultural and linguistic environments. We show that language-independent measurement of phoneme counts is somewhat more accurate than syllables or words, but all three are highly correlated with human annotations on the same data. We share an open-source implementation of ALICE for use by the language research community, enabling automatic phoneme, syllable, and word count estimation from child-centered audio recordings.

Accuracy of the Language Environment Analyses (LENATM) system for estimating child and adult speech in laboratory settings

Laboratory observations are a mainstay of language development research, but transcription is costly. We test whether speech recognition technology originally designed for day-long contexts can be usefully applied to this use-case. We compared automated adult word and child vocalization counts from Language Environment Analysis (LENATM) to those of transcribers in 20-minute play sessions with Spanish-speaking dyads (n = 104) at 1;7 and 2;2. For adult words, results indicated moderate associations but large absolute differences. Associations for child vocalizations were weaker with larger absolute discrepancies. LENA has moderate potential to ease the burden of transcription in some research and clinical applications.

Infants' neural speech discrimination predicts individual differences in grammar ability at 6 years of age and their risk of developing speech-language disorders

The 'sensitive period' for phonetic learning posits that between 6 and 12 months of age, infants' discrimination of native and nonnative speech sounds diverge. Individual differences in this dynamic processing of speech have been shown to predict later language acquisition up to 30 months of age, using parental surveys. Yet, it is unclear whether infant speech discrimination could predict longer-term language outcome and risk for developmental speech-language disorders, which affect up to 16 % of the population. The current study reports a prospective prediction of speech-language skills at a much later age-6 years-old-from the same children's nonnative speech discrimination at 11 months-old, indexed by MEG mismatch responses. Children's speech-language skills at 6 were comprehensively evaluated by a speech-language pathologist in two ways: individual differences in spoken grammar, and the presence versus absence of speech-language disorders. Results showed that the prefrontal MEG mismatch response at 11 months not only significantly predicted individual differences in spoken grammar skills at 6 years, but also accurately identified the presence versus absence of speech-language disorders, using a machine-learning classification. These results represent new evidence that advance our theoretical understanding of the neurodevelopmental trajectory of language acquisition and early risk factors for developmental speech-language disorders.

Exposure to electronic media between 6 and 24 months of age: An exploratory study

This study explores the associations between electronic media exposure, age, and socioeconomic status (SES) in a longitudinal sample of 24 infants from English-speaking families. Leveraging Language ENvironment Analysis (LENA) technology, the study seeks to characterize the relation between electronic media exposure and parental and child vocal activity. We analyzed ecologically valid, daylong audio recordings collected in infants' homes when they were 6, 10, 14, 18, and 24 months old. SES was measured with the Hollingshead Index, and exposure to electronic media and adult and infant vocal activity were measured automatically with LENA. On average, the children in the sample were exposed to 58 min of electronic media daily. We found that electronic media exposure was negatively associated with SES and decreased with child age, but only amongst high-SES families. We also found that electronic media exposure negatively impacted concurrent adult and child vocal activity, irrespective of SES and infant age. The present findings are an important step forward in examining the role of demographic factors in exposure to electronic media and enhance our understanding of the mechanisms through which exposure to electronic media may impact linguistic development in infancy and beyond.

Variations in the Home Language Environment and Early Language Development in Rural China

The home language environment is critical to early language development and subsequent skills. However, few studies have quantitatively measured the home language environment in low-income, developing settings. This study explores variations in the home language environment and child language skills among households in poor rural villages in northwestern China. Audio recordings were collected for 38 children aged 20-28 months and analyzed using Language Environment Analysis (LENA) software; language skills were measured using the MacArthur-Bates Mandarin Communicative Developmental Inventories expressive vocabulary scale. The results revealed large variability in both child language skills and home language environment measures (adult words, conversational turns, and child vocalizations) with 5- to 6-fold differences between the highest and lowest scores. Despite variation, however, the average number of adult words and conversational turns were lower than found among urban Chinese children. Correlation analyses did not identify significant correlations between demographic characteristics and the home language environment. However, the results do indicate significant correlations between the home language environment and child language skills, with conversational turns showing the strongest correlation. The results point to a need for further research on language engagement and ways to increase parent-child interactions to improve early language development among young children in rural China.

Unique contribution of shared book reading on adult-child language interaction

Researchers agree that early literacy activities, like book sharing and parent-child play, are important for stimulating language development. We hypothesize that book sharing is most powerful because it elicits more interactive talk in young children than other activities. Parents of 43 infants (9-18 months) made two daylong audio recordings using the LENA system. We compared a typical day, with spontaneous occurring activities, with an instructed day when caregivers were prompted to do book reading and toy play. Book sharing resulted in a combination of more parent talk, child talk, and interactions than other language activities. Research context did not influence outcomes: no differences were found in language use between the spontaneous and the instructed activities. Overall it seems clear that even with infants shared reading is a strong unique stimulator of language use from parent and child.

Comparing Automatic and Manual Measures of Parent-Infant Conversational Turns: A Word of Caution

The Language ENvironment Analysis system (LENA) records children’s language environment and provides an automatic estimate of adult–child conversational turn count (CTC). The present study compares LENA’s CTC estimate to manually coded CTC on a sample of 70 English‐speaking infants recorded longitudinally at 6, 10, 14, 18, and 24 months of age. At each age, LENA’s CTC was significantly higher than manually coded CTC (all ps < .001, Cohen’s ds: 0.9–2.05), with the largest discrepancies between the two methods observed at younger ages. The Limits of Agreement Analyses confirm wide disagreements between the two methods, highlighting potential problems with automatic measurement of parent–infant verbal interaction. These findings suggest that future studies should validate LENA’s CTC estimates with manual coding.

Language learning as a function of infant directed speech (IDS) in Spanish: Testing neural commitment using the positive-MMR

Spanish-English bilingual families (N = 17) were recruited to assess the association between infant directed speech (IDS) in Spanish and their degree of neural commitment to the Spanish language. IDS was assessed by extracting the caregivers' Vowel Space Area (VSA) from recordings of a storybook reading task done at home. Infants' neural commitment was assessed by extracting the positive mismatch brain response (positive-MMR), an Event-Related Potential (ERP) thought to be indicative of higher attentional processes and early language commitment. A linear mixed model analysis demonstrated that caregivers' VSA predicted the amplitude of the positive-MMR in response to a native speech contrast (Spanish), but not to a non-native speech contrast (Chinese), even after holding other predictors constant (i.e., socioeconomic status, infants' age, and fundamental frequency). Our findings provide support to the view that quality of language exposure fosters language learning, and that this beneficial relationship expands to the bilingual population.

Enhancing the NICU language environment with a neonatal Cuddler program

OBJECTIVE

To compare effects of a language intervention on Cuddler and parent adult word counts (AWC), and to compare Cuddler versus parent and nurse-care times.

DESIGN

Prospective pilot cohort intervention study. Twelve Cuddler-low-visit (≤2/week) infant pairs and 17 high-visit (≥3/week) parent-infant pairs were enrolled. Each had a 16-hour baseline recording (R1) followed by a language curriculum with linguistic feedback and an outcome recording (R2) 1 week later. Bivariate group analyses and longitudinal negative binomial regressions were run.

RESULTS

After the intervention, there were non-significant increases in AWC/h for Cuddlers and high-visit parents. Cuddler AWCs were similar to high-visit parents and significantly higher than nurse-care times on both recordings. Within the low-visit group, hourly AWCs were higher when Cuddlers were present versus absent (R1 = 1779 versus 552, R2 = 2530 versus 534, p < 0.0001).

CONCLUSIONS

NICU language environments are different for low-visit and high-visit infants and Cuddlers can increase infant language exposure in the NICU.

A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the multi-lab ManyBabies 1 project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants' preference for North-American English IDS (cf. ManyBabies Consortium, 2020: ManyBabies 1), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6-9 months (the younger sample) and 12-15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

Randomised control language intervention for infants of adolescent mothers

AIM

Create a Language ENvironment Analysis (LENA)-based intervention to increase adolescent and infant speech and improve 12-month language outcomes.

METHODS

Randomised control trial of adolescent (15-19 years) mother-infant pairs comparing language-motor (intervention) and motor (control) groups. Intervention included reviewing language-motor curriculums, formative feedback on 4 LENA recordings (baseline, post-curriculum, 4 and 12-months) and 16-weekly language-motor texts. Controls reviewed a motor curriculum, summative feedback of four recordings after study completion and 4-monthly motor texts. Primary outcome was 12-month MacArthur scores. Secondary outcomes were LENA counts and social impacts to language outcomes.

RESULTS

A total of 108 infants were randomised. Groups had similar baseline characteristics and LENA counts. Both groups had low maternal Peabody Picture Vocabulary age-equivalents (14.2 years). On post-curriculum recording, intervention infants had higher vocalisations (188 vs 109, P = .02) and conversations (49 vs 30, P = .005) than controls. Group 4-month and 12-month LENA counts and 12-month MacArthur scores were similar. In regression analyses, more people in the home and cohabiting with the infant's father were associated with higher MacArthur scores.

CONCLUSIONS

Linguistic feedback and a simple curriculum resulted in short-term increased vocalisations and conversational turns for infants of adolescent mothers that were not sustained over time. Household characteristics provided protective effects on outcomes.

Adult responses to infant prelinguistic vocalizations are associated with infant vocabulary: A home observation study

This study used LENA recording devices to capture infants' home language environments and examine how qualitative differences in adult responding to infant vocalizations related to infant vocabulary. Infant-directed speech and infant vocalizations were coded in samples taken from daylong home audio recordings of 13-month-old infants. Infant speech-related vocalizations were identified and coded as either canonical or non-canonical. Infant-directed adult speech was identified and classified into different pragmatic types. Multiple regressions examined the relation between adult responsiveness, imitating, recasting, and expanding and infant canonical and non-canonical vocalizations with caregiver-reported infant receptive and productive vocabulary. An interaction between adult like-sound responding (i.e., the total number of imitations, recasts, and expansions) and infant canonical vocalizations indicated that infants who produced more canonical vocalizations and received more adult like-sound responses had higher productive vocabularies. When sequences were analyzed, infant canonical vocalizations that preceded and followed adult recasts and expansions were positively associated with infant productive vocabulary. These findings provide insights into how infant-adult vocal exchanges are related to early vocabulary development.

Self-directed learning by preschoolers in a naturalistic overhearing context

Three studies investigated preschoolers' self-directed learning ability in a naturalistic context: learning from overheard speech. In Experiment 1, 4.5- to 6-year-olds were exposed to 4 novel words and 6 arbitrary facts corresponding to a set of co-present toys; in Experiment 2, 3- to 4.5-year-olds heard 5 nouns and 3 facts. In the Pedagogical conditions, children were taught the information with the aid of multiple pedagogical cues, but in the Overhearing conditions, children had to 'listen in' to one side of a phone call to learn the information. Older preschoolers (Experiment 1) learned all items above chance in both conditions. Younger preschoolers (Experiment 2) learned words and facts above chance in the Pedagogical condition, but were at chance at learning words in the Overhearing condition, despite reliably learning facts from overhearing. Experiment 3 demonstrated that younger children's difficulty at learning new words from overhearing could not be explained by only being able to hear one side of the phone conversation, as they similarly struggled when the phone call took place over speakerphone. Measures of children's touch behavior suggest that older children were better able to coordinate their attention between the overheard speech and objects, though even younger children showed evidence of attention to the overheard speech. Together, our results demonstrate that by age 5, children can learn multiple new words and facts via overhearing. This self-directed learning ability depends on being able to coordinate attention between speech and the surrounding environment, a capacity that develops throughout preschool.

Longform recordings of everyday life: Ethics for best practices

Recent advances in large-scale data storage and processing offer unprecedented opportunities for behavioral scientists to collect and analyze naturalistic data, including from underrepresented groups. Audio data, particularly real-world audio recordings, are of particular interest to behavioral scientists because they provide high-fidelity access to subtle aspects of daily life and social interactions. However, these methodological advances pose novel risks to research participants and communities. In this article, we outline the benefits and challenges associated with collecting, analyzing, and sharing multi-hour audio recording data. Guided by the principles of autonomy, privacy, beneficence, and justice, we propose a set of ethical guidelines for the use of longform audio recordings in behavioral research. This article is also accompanied by an Open Science Framework Ethics Repository that includes informed consent resources such as frequent participant concerns and sample consent forms.

The role of caregiver speech in supporting language development in infants and toddlers with autism spectrum disorder

Parents play an essential role in supporting child development by providing a safe home, proper nutrition, and rich educational opportunities. In this article we focus on the role of caregiver speech in supporting development of young children with autism spectrum disorder (ASD). We review studies from typically developing children and children with autism showing that rich and responsive caregiver speech supports language development. Autism intervention studies that target caregiver speech are reviewed as are recent scientific advances from studies of typical development. The strengths and weakness of different techniques for collecting language data from caregivers and children are reviewed, and natural language samples are recommended as best practice for language research in autism. We conclude that caregivers play a powerful role in shaping their children's development and encourage researchers to adapt parent-mediated intervention studies to acknowledge individual differences in parents by using a personalized medicine approach.

Early word-learning skills: A missing link in understanding the vocabulary gap?

Socioeconomic status (SES) has been repeatedly linked to the developmental trajectory of vocabulary acquisition in young children. However, the nature of this relationship remains underspecified. In particular, despite an extensive literature documenting young children's reliance on a host of skills and strategies to learn new words, little attention has been paid to whether and how these skills relate to measures of SES and vocabulary acquisition. To evaluate these relationships, we conducted two studies. In Study 1, 205 2.5- to 3.5-year-old children from widely varying socioeconomic backgrounds were tested on a broad range of word-learning skills that tap their ability to resolve cases of ambiguous reference and to extend words appropriately. Children's executive functioning and phonological memory skills were also assessed. In Study 2, 77 of those children returned for a follow-up session several months later, at which time two additional measures of vocabulary were obtained. Using Structural Equation Modeling (SEM) and multivariate regression, we provide evidence of the mediating role of word-learning skills on the relationship between SES and vocabulary skill over the course of early development.

The Natural Language Environment of 9-Month-Old Infants in Sweden and Concurrent Association With Early Language Development

The language environment is important for the development of early communication and language. In the current study, we describe the natural home language environment of 9-month-old infants in Sweden and its concurrent association with language development. Eighty-eight families took part in the study. The home language environment was measured using the Language ENvironment Analysis (LENA) system, and language development was assessed using Swedish Early Communicative Development Inventory (SECDI), a parent questionnaire. LENA measures showed dramatic variation between individuals but were comparable to and showed overlapping variance with previous studies conducted in English-speaking households. Nonetheless, there were significantly more infant vocalizations and conversational turns in the present study than in one previous study. Adult word count correlated significantly and positively with infants' Use of gestures and the subscale of that section Communicative gestures. These together with another four non-significant associations formed a consistent overall pattern that suggested a link between infants' language environment and language development. Although the direction of causality cannot be determined from the current data, future studies should examine children longitudinally to assess the directionality or the bidirectionality of the reported associations between infant's language environment and language development.

6- to 9-Month old infants discriminate vowel durations in variable speech contexts

Discriminating temporal relationships in speech is crucial for speech and language development. However, temporal variation of vowels is difficult to perceive for young infants when it is determined by surrounding speech sounds. Using a familiarization-discrimination paradigm, we show that English-learning 6- to 9-month-olds are capable of discriminating non-native acoustic vowel duration differences that systematically vary with subsequent consonantal durations. Furthermore, temporal regularity of stimulus presentation potentially makes the task easier for infants. These findings show that young infants can process fine-grained temporal aspects of speech sounds, a capacity that lays the foundation for building a phonological system of their ambient language(s).

Social and endogenous infant vocalizations

Research on infant vocal development has provided notable insights into vocal interaction with caregivers, elucidating growth in foundations for language through parental elicitation and reaction to vocalizations. A role for infant vocalizations produced endogenously, potentially providing raw material for interaction and a basis for growth in the vocal capacity itself, has received less attention. We report that in laboratory recordings of infants and their parents, the bulk of infant speech-like vocalizations, or "protophones", were directed toward no one and instead appeared to be generated endogenously, mostly in exploration of vocal abilities. The tendency to predominantly produce protophones without directing them to others occurred both during periods when parents were instructed to interact with their infants and during periods when parents were occupied with an interviewer, with the infants in the room. The results emphasize the infant as an agent in vocal learning, even when not interacting socially and suggest an enhanced perspective on foundations for vocal language.

Depression and Anxiety in the Postnatal Period: An Examination of Infants' Home Language Environment, Vocalizations, and Expressive Language Abilities

This longitudinal study investigated the effects of maternal emotional health concerns, on infants' home language environment, vocalization quantity, and expressive language skills. Mothers and their infants (at 6 and 12 months; 21 mothers with depression and or anxiety and 21 controls) provided day-long home-language recordings. Compared with controls, risk group recordings contained fewer mother-infant conversational turns and infant vocalizations, but daily number of adult word counts showed no group difference. Furthermore, conversational turns and infant vocalizations were stronger predictors of infants' 18-month vocabulary size than depression and anxiety measures. However, anxiety levels moderated the effect of conversational turns on vocabulary size. These results suggest that variability in mothers' emotional health influences infants' language environment and later language ability.

Cognitive Stimulation as a Mechanism Linking Socioeconomic Status With Executive Function: A Longitudinal Investigation

Executive functions (EF), including working memory, inhibition, and cognitive flexibility, vary as a function of socioeconomic status (SES), with children from economically disadvantaged backgrounds having poorer performance than their higher SES peers. Using observational methods, we investigated cognitive stimulation in the home as a mechanism linking SES with EF. In a sample of 101 children aged 60-75 months, cognitive stimulation fully mediated SES-related differences in EF. Critically, cognitive stimulation was positively associated with the development of inhibition and cognitive flexibility across an 18-month follow-up period. Furthermore, EF at T1 explained SES-related differences in academic achievement at T2. Early cognitive stimulation-a modifiable factor-may be a desirable target for interventions designed to ameliorate SES-related differences in cognitive development and academic achievement.

Individual differences in non-adjacent statistical dependency learning in infants

There is considerable controversy over the factors that shape infants' developing knowledge of grammar. Work with artificial languages suggests that infants' ability to track statistical regularities within the speech they hear could, in principle, support grammatical development. However, little work has tested whether infants' performance on laboratory tasks reflects factors that are relevant in real-world language learning. Here we tested whether the language that infants hear at home, and their receptive language skills, predict their performance on tasks assessing the ability to learn non-adjacent statistical dependencies (NADs) at 15 months, and whether that in turn predicts sensitivity to native-language NADs at 18 months. We found evidence for some (though not all) of these relations, and primarily for females. The results suggest that performance on the artificial language-learning task reveals something about the mechanisms of grammatical development, and that females and males may be learning NADs differently.

The effect of infant-directed speech on early multimodal communicative production in Spanish and Basque

We analyzed the effect of infant-directed speech (IDS) on multimodal communicative production of children at the beginning of the second year of life in two different languages: Spanish and Basque. Twelve Spanish and twelve Basque children aged between 12 and 15 months observed two versions of an audiovisual story: one version was narrated with IDS and the other with adult-directed speech (ADS). We analyzed the use of gaze and the communicative behaviors produced by children. The time spent looking at the story increases in the IDS condition regardless of the language of the narration. Children produced more multimodal communicative behaviors while watching the IDS version both in Spanish and in Basque. These results suggest that IDS increases attention and social engagement promoting joint attention episodes.

The role of maternal psychosocial perceptions in parent-training programs: a preliminary randomized controlled trial

Parent-child interaction is critical for early language and literacy development. Parent training programs have proliferated to support early interactions. However, many environmental and psychosocial factors can impact the quality of parent-child language and literacy interactions as well as training program outcomes. This preliminary randomized controlled trial examined maternal perceived self-efficacy and locus of control during a language and literacy parent training program. Thirty mother-child dyads (mother age 21-40; children 2;6-4;0) were assigned in parallel to the training or control group. The training was efficacious for mothers and children - training-group dyads made significantly greater gains in maternal strategy use, responsivity, and child print awareness than the control group. Gains were maintained one month post-training. Children whose mothers had more external baseline control perceptions identified significantly fewer print targets at baseline and made greater gains than those with more internal control perceptions. Future directions and implications are discussed.

The Relationship Between the Onset of Canonical Syllables and Speech Perception Skills in Children With Cochlear Implants

Purpose The study sought to determine whether the onset of canonical vocalizations in children with cochlear implants (CIs) is related to speech perception skills and spoken vocabulary size at 24 months postactivation. Method The vocal development in 13 young CI recipients (implanted by their third birthdays; mean age at activation = 20.62 months, SD = 8.92 months) was examined at every 3-month interval during the first 2 years of CI use. All children were enrolled in auditory-oral intervention programs. Families of these children used spoken English only. To determine the onset of canonical syllables, the first 50 utterances from 20-min adult-child interactions were analyzed during each session. The onset timing was determined when at least 20% of utterances included canonical syllables. As children's outcomes, we examined their Lexical Neighborhood Test scores and vocabulary size at 24 months postactivation. Results Pearson correlation analysis showed that the onset timing of canonical syllables is significantly correlated with phonemic recognition skills and spoken vocabulary size at 24 months postactivation. Regression analyses also indicated that the onset timing of canonical syllables predicted phonemic recognition skills and spoken vocabulary size at 24 months postactivation. Conclusion Monitoring vocal advancement during the earliest periods following cochlear implantation could be valuable as an early indicator of auditory-driven language development in young children with CIs. It remains to be studied which factors improve vocal development for young CI recipients.

Parent coaching increases conversational turns and advances infant language development

Parental language input is one of the best predictors of children's language achievement. Parentese, a near-universal speaking style distinguished by higher pitch, slower tempo, and exaggerated intonation, has been documented in speech directed toward young children in many countries. Previous research shows that the use of parentese and parent-child turn-taking are both associated with advances in children's language learning. We conducted a randomized controlled trial to determine whether a parent coaching intervention delivered when the infants are 6, 10, and 14 mo of age can enhance parental language input and whether this, in turn, changes the trajectory of child language development between 6 and 18 mo of age. Families of typically developing 6-mo-old infants (n = 71) were randomly assigned to intervention and control groups. Naturalistic first-person audio recordings of the infants' home language environment and vocalizations were recorded when the infants were 6, 10, 14, and 18 mo of age. After the 6-, 10-, and 14-mo recordings, intervention, but not control parents attended individual coaching appointments to receive linguistic feedback, listen to language input in their own recordings, and discuss age-appropriate activities that promote language growth. Intervention significantly enhanced parental use of parentese and parent-child turn-taking between 6 and 18 mo. Increases in both variables were significantly correlated with children's language growth during the same period, and children's language outcomes at 18 mo. Using parentese, a socially and linguistically enhanced speaking style, improves children's social language turn-taking and language skills. Research-based interventions targeting social aspects of parent-child interactions can enhance language outcomes.

Pitch properties of infant-directed speech specific to word-learning contexts: a cross-linguistic investigation of Mandarin Chinese and Dutch

This study investigates the pitch properties of infant-directed speech (IDS) specific to word-learning contexts in which mothers introduce unfamiliar words to children. Using a semi-spontaneous story-book telling task, we examined (1) whether mothers made distinctions between unfamiliar and familiar words with pitch in IDS compared to adult-directed speech (ADS); (2) whether pitch properties change when mothers address children from 18 to 24 months; and (3) how Mandarin Chinese and Dutch IDS differ in their pitch properties in word-learning contexts. Results show that the mean pitch of Mandarin Chinese IDS was already ADS-like when children were 24 months, but Dutch IDS remained exaggerated in pitch at the same age. Crucially, Mandarin Chinese mothers used a higher pitch and a larger pitch range in IDS when introducing unfamiliar words, while Dutch mothers used a higher pitch specifically for familiar words. These findings contribute to the language-specificity of prosodic input in early lexical development.

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.

What do bilingual infants actually hear? Evaluating measures of language input to bilingual-learning 10-month-olds

Examining how bilingual infants experience their dual language input is important for understanding bilingual language acquisition. To assess these language experiences, researchers typically conduct language interviews with caregivers. However, little is known about the reliability of these parent reports in describing how bilingual children actually experience dual language input. Here, we explored the quantitative nature of dual language input to bilingual infants. Furthermore, we described some of the heterogeneity of bilingual exposure in a sample of French-English bilingual families. Participants were 21 families with a 10-month-old infant residing in Montréal, Canada. First, we conducted language interviews with the caregivers. Then, each family completed three full-day recordings at home using the Language Environment Analysis recording system. Results showed that children's proportion exposure to each language was consistent across the two measurement approaches, indicating that parent reports are reliable for assessing a bilingual child's language experiences. Further exploratory analyses revealed three unique findings: (a) there can be considerable variability in the absolute amount of input among infants hearing the same proportion of input, (b) infants can hear different proportions of language input when considering infant-directed versus overheard speech, (c) proportion of language input can vary by day, depending on who is caring for the infant. We conclude that collecting naturalistic recordings is complementary to parent-report measures for assessing infant's language experiences and for establishing bilingual profiles.

The current standing of bilingualism in today's globalized world: a socio-ecological perspective

Globalization has made interactions between individuals from different cultures and languages unavoidable. Therefore, questions concerning bilingualism have become increasingly important within the scholarly community. In this paper, we review this emerging research using a socio-ecological approach. We first present evidence that demonstrates how learning two languages is dependent upon the socio-ecologies of individuals. Second, we review studies that show how bilingualism promotes a myriad of positive social advantages. Then we discuss how the positive effects of bilingualism has affected the socio-ecologies of the individuals. Our discussion sheds light on the challenges that caregivers, educators, scientists, and policy makers face to promote bilingualism in today's globalized world. WC=106/150.

The Effect of Older Siblings on Language Development as a Function of Age Difference and Sex

The number of older siblings a child has is negatively correlated with the child’s verbal skills, perhaps because of competition for parents’ attention. In the current study, we examined the role of siblings’ sex and age gap as moderating factors, reasoning that they affect older siblings’ tendency to compensate for reduced parental attention. We hypothesized that children with an older sister have better language abilities than children with an older brother, especially when there is a large age gap between the two siblings. We reanalyzed data from the EDEN cohort ( N = 1,154) and found that children with an older sister had better language skills than those with an older brother. Contrary to predictions, results showed that the age gap between siblings was not associated with language skills and did not interact with sex. Results suggest that the negative effect of older siblings on language development may be entirely due to the role of older brothers. Our findings invite further research on the mechanisms involved in this effect.

Reliability of the Language Environment Analysis Recording System in Analyzing French-English Bilingual Speech

Purpose This study examined the utility of the Language ENvironment Analysis (LENA) recording system for investigating the language input to bilingual infants. Method Twenty-one French-English bilingual families with a 10-month-old infant participated in this study. Using the LENA recording system, each family contributed 3 full days of recordings within a 1-month period. A portion of these recordings (945 minutes) were manually transcribed, and the word counts from these transcriptions were compared against the LENA-generated adult word counts. Results Data analyses reveal that the LENA algorithms were reliable in counting words in both Canadian English and Canadian French, even when both languages are present in the same recording. While the LENA system tended to underestimate the amount of speech in the recordings, there was a strong correlation between the LENA-generated and human-transcribed adult word counts for each language. Importantly, this relationship holds when accounting for different-gendered and different-accented speech. Conclusions The LENA recording system is a reliable tool for estimating word counts, even for bilingual input. Special considerations and limitations for using the LENA recording system in a bilingual population are discussed. These results open up possibilities for investigating caregiver talk to bilingual infants in more detail.

Intersensory redundancy promotes infant detection of prosody in infant-directed speech

Prosody, or the intonation contours of speech, conveys emotion and intention to the listener and provides infants with an early basis for detecting meaning in speech. Infant-directed speech (IDS) is characterized by exaggerated prosody, slower tempo, and elongated pauses, all amodal properties detectable across the face and voice. Although speech is an audiovisual event, it has been studied primarily as a unimodal auditory stream without the synchronized dynamic face of the speaker. According to the intersensory redundancy hypothesis, redundancy across the senses facilitates perceptual learning of amodal information, including prosody. We predicted that young infants who are still learning to discriminate and categorize prosodic information would detect prosodic changes better in the presence of intersensory redundancy (i.e., synchronous audiovisual speech) than in its absence (i.e., unimodal auditory or asynchronous audiovisual speech). To test this hypothesis, 72 4-month-old infants were habituated to recordings of women reciting passages in IDS with prosody conveying either approval or prohibition and then were tested with recordings of a novel passage with either a change or no change in prosody. Infants who received bimodal synchronous stimulation exhibited significant visual recovery to the novel passage with a change in prosody, but not to a novel passage with no change in prosody. Infants in the unimodal auditory and bimodal asynchronous conditions did not exhibit visual recovery in either condition. Results support the hypothesis that intersensory redundancy facilitates detection and abstraction of invariant prosody across changes in linguistic content and likely serves as an early foundation for the detection of meaning in fluent speech.

Impact of Nonmedical Factors on Neurobehavior and Language Outcomes of Preterm Infants

Preterm infants are at increased risk for adverse neurodevelopmental outcomes. The impact of maternal, NICU, and social environmental factors on early neurobehavior and language outcomes of preterm infants is recognized. There is a need for health care professionals to have a clear understanding of the importance of facilitating positive mother-infant relationships, and to address not only the infant's sensory and language environment, but also focus on adverse maternal mental health and social adversities to optimize infant outcomes.

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.

A step-by-step guide to collecting and analyzing long-format speech environment (LFSE) recordings

Recent years have seen rapid technological development of devices that can record communicative behavior as participants go about daily life. This paper is intended as an end-to-end methodological guidebook for potential users of these technologies, including researchers who want to study children’s or adults’ communicative behavior in everyday contexts. We explain how long-format speech environment (LFSE) recordings provide a unique view on language use and how they can be used to complement other measures at the individual and group level. We aim to help potential users of these technologies make informed decisions regarding research design, hardware, software, and archiving. We also provide information regarding ethics and implementation, issues that are difficult to navigate for those new to this technology, and on which little or no resources are available. This guidebook offers a concise summary of information for new users and points to sources of more detailed information for more advanced users. Links to discussion groups and community-augmented databases are also provided to help readers stay up-to-date on the latest developments.

Demystifying infant vocal imitation: The roles of mouth looking and speaker's gaze

Vocal imitation plays a fundamental role in human language acquisition from infancy. Little is known, however, about how infants imitate other's sounds. We focused on three factors: (a) whether infants receive information from upright faces, (b) the infant's observation of the speaker's mouth and (c) the speaker directing their gaze towards the infant. We recorded the eye movements of 6-month-olds who participated in experiments watching videos of a speaker producing vowel sounds. We found that an infants' tendency to vocally imitate such videos increased as a function of (a) seeing upright rather than inverted faces, (b) their increased looking towards the speaker's mouth and (c) whether the speaker directed their gaze towards, rather than away from infants. These latter findings are consistent with theories of motor resonance and natural pedagogy respectively. New light has been shed on the cues and underlying mechanisms linking infant speech perception and production.