Temporal Responsiveness in Mother-Child Dialogue: A Longitudinal Analysis of Children with Normal Hearing and Hearing Loss

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

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

Development of full-body rhythmic synchronization in middle childhood

Rhythmic entrainment is a fundamental aspect of musical behavior, but the skills required to accurately synchronize movement to the beat seem to develop over many years. Motion capture studies of corporeal synchronization have shown immature abilities to lock in to the beat in children before age 5, and reliable synchronization ability in adults without musical training; yet there is a lack of data on full-body synchronization skills between early childhood and adulthood. To document typical rhythmic synchronization during middle childhood, we used a wireless motion capture device to measure period- and phase-locking of full body movement to rhythm and metronome stimuli in 6 to 11 year-old children in comparison with adult data. Results show a gradual improvement with age; however children's performance did not reach adult levels by age 12, suggesting that these skills continue to develop during adolescence. Our results suggest that in the absence of specific music training, full-body rhythmic entrainment skills improve gradually during middle childhood, and provide metrics for examining the continued maturation of these skills during adolescence.

The role of lexical and prosodic characteristics of mothers' child-directed speech for the early vocabulary development of Italian children with cochlear implants

BACKGROUND

Variability in the vocabulary outcomes of children with cochlear implants (CIs) is partially explained by child-directed speech (CDS) characteristics. Yet, relatively little is known about whether and how mothers adapt their lexical and prosodic characteristics to the child's hearing status (before and after implantation, and compared with groups with normal hearing (NH)) and how important they are in affecting vocabulary development in the first 12 months of hearing experience.

AIMS

To investigate whether mothers of children with CIs produce CDS with similar lexical and prosodic characteristics compared with mothers of age-matched children with NH, and whether they modify these characteristics after implantation. In addition, to investigate whether mothers' CDS characteristics predict children's early vocabulary skills before and after implantation.

METHODS & PROCEDURES

A total of 34 dyads (17 with NH, 17 with children with CIs; ages = 9-32 months), all acquiring Italian, were involved in the study. Mothers' and children's lexical quantity (tokens) and variety (types), mothers' prosodic characteristics (pitch range and variability), and children's vocabulary skills were assessed at two time points, corresponding to before and 1 year post-CI activation for children with CIs. Children's vocabulary skills were assessed using parent reports; lexical and prosodic characteristics were observed in semi-structured mother-child interactions.

OUTCOMES & RESULTS

Results showed that mothers of children with CIs produced speech with similar lexical quantity but lower lexical variety, and with increased pitch range and variability, than mothers of children with NH. Mothers generally increased their lexical quantity and variety and their pitch range between sessions. Children with CIs showed reduced expressive vocabulary and lower lexical quantity and variety than their peers 12 months post-CI activation. Mothers' prosodic characteristics did not explain variance in children's vocabulary skills; their lexical characteristics predicted children's early vocabulary and lexical outcomes, especially in the NH group, but were not related to later language development.

CONCLUSIONS & IMPLICATIONS

Our findings confirm previous studies on other languages and support the idea that the lexical characteristics of mothers' CDS have a positive effect on children's early measures of vocabulary development across hearing groups, whereas prosodic cues play a minor role. Greater input quantity and quality may assist children in the building of basic language model representations, whereas pitch cues may mainly serve attentional and emotional processes. Results emphasize the need for additional longitudinal studies investigating the input received from other figures surrounding the child and its role for children's language development.

WHAT THIS PAPER ADDS

What is already known on the subject Mothers' CDS is thought to facilitate and support language acquisition in children with various language developmental trajectories, including children with CIs. Because children with CIs are at risk for language delays and have acoustic processing limitations, their mothers may have to produce a lexically simpler but prosodically richer input, compared to mothers of children with NH. Yet, the literature reports mixed findings and no study to our knowledge has concurrently addressed the role of mothers' lexical and prosodic characteristics for children's vocabulary development before implantation and in the first 12 months of hearing experience. What this study adds to the existing knowledge The study shows that mothers of children with CIs produce input of similar quantity but reduced variety, and with heightened pitch characteristics, compared to mothers of children with NH. There was also a general increase in mothers' lexical quantity and variety, and in their pitch range, between sessions. Only their lexical characteristics predicted children's early vocabulary skills. Their lexical variety predicted children's expressive vocabulary and lexical variety only in the NH group. What are the practical and clinical implications of this work? These findings expand our knowledge about the effects of maternal input and may contribute to the improvement of early family-centred intervention programmes for supporting language development in children with CIs.

The effect of telepractice on vocal turn-taking between a provider, children with cochlear implants, and caregivers: A preliminary report

OBJECTIVES

To examine the effect of telepractice on vocal turn-taking between one clinical provider and children with cochlear implants and their caregivers during child-centered auditory rehabilitation intervention.

METHODS

Seven dyads of children with cochlear implants (mean age 4:11 years) and their hearing mothers and one speech-language pathologist participated together in a telepractice session and an in-person intervention session. Dependent variables were vocalization rate, turn taking rate, rate of speech overlap per second, and between-speaker pause duration.

RESULTS

The speech-language pathologist and children had lower rates of vocalization in the telepractice session than the in-person session. However, maternal vocalization rate was higher in the telepractice than in-person session. The rate of turn-taking between the provider and children was lower in telepractice than in-person sessions but the rate of turn taking between mothers and children was higher in telepractice than in-person sessions. Between-speaker pause duration between children and the provider and between mothers and children was longer in telepractice than in-person sessions. Rate of speech overlap did not vary significantly by session type.

DISCUSSION

The quantity and temporal characteristics of vocal turn-taking were impacted by remote communication during tele-intervention suggesting a potential increase in the cognitive effort required of participants.

Child language and autism diagnosis impact hierarchical temporal structure of parent-child vocal interactions in early childhood

Timing is critical to successful social interactions. The temporal structure of dyadic vocal interactions emerges from the rhythm, timing, and frequency of each individuals' vocalizations and reflects how the dyad dynamically organizes and adapts during an interaction. This study investigated the temporal structure of vocal interactions longitudinally in parent-child dyads of typically developing (TD) infants (n = 49; 9-18 months; 48% male) and toddlers with ASD (n = 23; 27.2 ± 5.0 months; 91.3% male) to identify how developing language and social skills impact the temporal dynamics of the interaction. Acoustic hierarchical temporal structure (HTS), a measure of the nested clustering of acoustic events across multiple timescales, was measured in free play interactions using Allan Factor. HTS reflects a signal's temporal complexity and variability, with greater HTS indicating reduced flexibility of the dyadic system. Child expressive language significantly predicted HTS (ß = -0.2) longitudinally across TD infants, with greater dyadic HTS associated with lower child language skills. ASD dyads exhibited greater HTS (i.e., more rigid temporal structure) than nonverbal matched (d = 0.41) and expressive language matched TD dyads (d = 0.28). Increased HTS in ASD dyads occurred at timescales >1 s, suggesting greater structuring of pragmatic aspects of interaction. Results provide a new window into how language development and social reciprocity serve as constraints to shape parent-child interaction dynamics and showcase a novel automated approach to characterizing vocal interactions across multiple timescales during early childhood.

Vocal Turn-Taking in Families With Children With and Without Hearing Loss

OBJECTIVE

Vocal turn-taking is an important predictor of language development in children with and without hearing loss. Most studies have examined vocal turn-taking in mother-child dyads without considering the multitalker context in a child's life. The present study investigates the quantity of vocal turns between deaf and hard-of-hearing children and multiple members of their social environment.

DESIGN

Participants were 52 families with children who used hearing aids (HA, mean age 26.3 mo) or cochlear implants (CI, mean age 63.2 mo) and 27 families with normal-hearing (NH, mean age 26.6 mo) children. The Language ENvironment Analysis system estimated the number of conversational turns per hour (CTC/hr) between all family members (i.e., adult female, adult male, target child, and other child) during full-day recordings over a period of about 1 year.

RESULTS

The CTC/hr was lower between the target child and the adult female or adult male in the CI compared with the HA and NH groups. Initially, CTC/hr was higher between the target child and the adult female than between the adult male or the other child. As the child's age increased, turn-taking between the target child and the adult female increased in comparison to that between the target child and the adult male. Over time, turn-taking between the target child and the other child increased and exceeded turn-taking between the target child and the adult caregivers. The increase was observed earlier in families with siblings compared with those without.

CONCLUSIONS

The quantity of vocal turn-taking depends on the degree of child hearing loss and the relationship between the children and the members of their social environment. Longitudinally, the positive effect of an assistive device on the quantity of turns between the children and their family members was found. The effect was stronger in families with siblings.

Differential At-Risk Pediatric Outcomes of Parental Sensitivity Based on Hearing Status

Purpose The aim of this study was to investigate the role of parental sensitivity in language and neurocognitive outcomes in children who are deaf and/or hard of hearing (DHH). Method Sixty-two parent-child dyads of children with normal hearing (NH) and 64 of children who are DHH (3-8 years) completed parent and child measures of inhibitory control/executive functioning and child measures of sentence comprehension and vocabulary. The dyads also participated in a video-recorded, free-play interaction that was coded for parental sensitivity. Results There was no evidence of associations between parental sensitivity and inhibitory control or receptive language in children with NH. In contrast, parental sensitivity was related to children's inhibitory control and all language measures in children who are DHH. Moreover, inhibitory control significantly mediated the association between parental sensitivity and child language on the Clinical Evaluation of Language Fundamentals-Fifth Edition Following Directions subscale (6-8 years)/Clinical Evaluation of Language Fundamentals Preschool-Second Edition Concepts and Following Directions subscale (3-5 years). Follow-up analyses comparing subgroups of children who used hearing aids (n = 29) or cochlear implants (CIs; n = 35) revealed similar correlational trends, with the exception that parental sensitivity showed little relation to inhibitory control in the group of CI users. Conclusions Parental sensitivity is associated with at-risk language outcomes and disturbances in inhibitory control in young children who are DHH. Compared to children with NH, children who are DHH may be more sensitive to parental behaviors and their effects on emerging inhibitory control and spoken language. Specifically, inhibitory control, when scaffolded by positive parental behaviors, may be critically important for robust language development in children who are DHH.

Prosodic cues in infant-directed speech facilitate young children's conversational turn predictions

Experienced language users are able to predict when conversational turns approach completion, which allows them to attend to and comprehend their interlocutor's speech while planning and accurately timing their response. Adults primarily rely on lexico-syntactic cues to make such predictions, but it remains unknown what cues support these predictions in young children whose lexico-syntactic competence is still developing. This study assessed children's reliance on prosodic cues, specifically when predicting conversational turn transitions in infant-directed speech (IDS), the speech register that they encounter in day-to-day interactions that is characterized by exaggerated prosody compared with adult-directed speech (ADS). Young children (1- and 3-year-olds) completed an anticipatory looking paradigm in which their gaze patterns were recorded while they observed conversations that were produced in IDS or ADS and that contained prosodically complete utterances (lexico-syntactic and prosodic cues) and prosodically incomplete utterances (only lexico-syntactic cues). The 1-year-olds anticipated more turns that were signaled by prosodic cues (i.e., prosodically complete utterances) only in IDS, whereas the 3-year-olds did so in both IDS and ADS. These findings indicate that children anticipate the completion of conversational turns by relying on prosodic information in speech and that the prosodic exaggeration of IDS supports this ability while children's linguistic and conversational skills are still developing.

Quantity and Quality of Parental Utterances and Responses to Children With Hearing Loss Prior to Cochlear Implant

This study investigated the extent to which parental language input to children with hearing loss (HL) prior to cochlear implant (CI) differs from input to children with typical hearing (TH). A 20-min parent-child interaction sample was collected for 13 parent-child dyads in the HL group and 17 dyads in the TH group during free play. Ten minutes were transcribed and were coded for four variables: (a) overall utterances, (b) high-quality utterances, (c) utterances in response to child communicative acts (i.e., overall responses), and (d) high-quality utterances in response to child communicative acts (i.e., high-quality responses). Differences were detected for both quantity and quality of parental language input across the two groups. Early language skills correlated with three out of the four parental variables in both groups. Post hoc analyses suggested that the lower rate of high-quality responses in parents of children with HL could be attributed to lower intelligibility of child communication.

Temporal Coordination in Mother-Infant Vocal Interaction: A Cross-Cultural Comparison

Temporal coordination of vocal exchanges between mothers and their infants emerges from a developmental process that relies on the ability of communication partners to co-coordinate and predict each other's turns. Consequently, the partners engage in communicative niche construction that forms a foundation for language in human infancy. While robust universals in vocal turn-taking have been found, differences in the timing of maternal and infant vocalizations have also been reported across cultures. In this study, we examine the temporal structure of vocal interactions in 38 mother-infant dyads in the first two years across two cultures-American and Lebanese-by studying observed and randomized distributions of vocalizations, focusing on both gaps and overlaps in naturalistic 10-min vocal interactions. We conducted a series of simulations using Kolmogorov-Smirnov (K-S) tests to examine whether the observed responsivity patterns differed from randomly generated simulations of responsivity patterns in both Arabic and English for mothers responding to infants and for infants responding to mothers. Results revealed that both mothers and infants engaged in conversational alternation, with mothers acting similarly across cultures. By contrast, significant differences were observed in the timing of infant responses to maternal utterances, with the Lebanese infants' tendency to cluster their responses in the first half-second after the offset of the Lebanese mothers' utterances to a greater extent than their American counterparts. We speculate that the results may be due to potential phonotactic differences between Arabic and English and/or to differing child-rearing practices across Lebanese and American cultures. The findings may have implications for early identification of developmental disorders such as autism spectrum disorders within and across cultures.

Vocal and Tactile Input to Children Who Are Deaf or Hard of Hearing

Purpose Caregivers may show greater use of nonauditory signals in interactions with children who are deaf or hard of hearing (DHH). This study explored the frequency of maternal touch and the temporal alignment of touch with speech in the input to children who are DHH and age-matched peers with normal hearing. Method We gathered audio and video recordings of mother-child free-play interactions. Maternal speech units were annotated from audio recordings, and touch events were annotated from video recordings. Analyses explored the frequency and duration of touch events and the temporal alignment of touch with speech. Results Greater variance was observed in the frequency of touch and its total duration in the input to children who are DHH. Furthermore, touches produced by mothers of children who are DHH were significantly more likely to be aligned with speech than touches produced by mothers of children with normal hearing. Conclusion Caregivers' modifications in the input to children who are DHH are observed in the combination of speech with touch. The implications for such patterns and how they may impact children's attention and access to the speech signal are discussed.