Infant-directed Speech Research Articles

Infants’ brain responses to social interaction predict future language growth

In face-to-face interactions with infants, human adults exhibit a species-specific communicative signal. Adults present a distinctive "social ensemble": they use infant-directed speech (parentese), respond contingently to infants' actions and vocalizations, and react positively through mutual eye-gaze and smiling. Studies suggest that this social ensemble is essential for initial language learning. Our hypothesis is that the social ensemble attracts attentional systems to speech and that sensorimotor systems prepare infants to respond vocally, both of which advance language learning. Using infant magnetoencephalography (MEG), we measure 5-month-old infants' neural responses during live verbal face-to-face (F2F) interaction with an adult (social condition) and during a control (nonsocial condition) in which the adult turns away from the infant to speak to another person. Using a longitudinal design, we tested whether infants' brain responses to these conditions at 5months of age predicted their language growth at five future time points. Brain areas involved in attention (right hemisphere inferior frontal, right hemisphere superior temporal, and right hemisphere inferior parietal) show significantly higher theta activity in the social versus nonsocial condition. Critical to theory, we found that infants' neural activity in response to F2F interaction in attentional and sensorimotor regions significantly predicted future language development into the third year of life, more than 2 years after the initial measurements. We develop a view of early language acquisition that underscores the centrality of the social ensemble, and we offer new insight into the neurobiological components that link infants' language learning to their early brain functioning during social interaction.

Temporal Characteristics of Infant Vocalization during Interaction with Adults

Objectives: This study aimed to examine the temporal characteristics of infant vocalizations during interactions with adults in natural home environments.Methods: One day LENA (Language ENvironment Analysis) recordings were collected from 20 infants aged 6 and 12 months. The collected data were analyzed by selecting 20 5-mintue intervals in the order of highest CTCs (conversational turn counts). In the analysis unit of turn-taking, interactions in which the infant responded within 0.05 seconds to 3 seconds after the adult spoke directly to the infant were regarded as one analysis unit. The temporal characteristics of infant vocalization during interactions with adults were examined through infants’ Vocalization response ratio. The temporal characteristics of infant vocalization in interactions with adults were examined by the after adults’ infant-directed speech (IDS), latency of vocalization response and overlapping vocalization ratio.Results: Infants’ Vocalization response ratio following IDS in adults did not differ significantly between the two age groups. Infants’ Vocalization response latencies increased significantly with age from 6 to 12 months. Overlapping vocalization ratio showed a significant decrease with increasing age.Conclusion: This study supports that as infants grow, they acquire temporal turn-taking skills. It also suggests that the temporal characteristics of infant vocalizations during interactions with adults may be a useful to predict infants’ language development.

Активни деривационни процеси при съществителните в руската реч, насочена към децата

Colloquial Russian has a rich set of productive derivation patterns used in informal registers directed to children, other relatives, friends or pets. This paper considers the most frequent patterns in child directed speech (CDS), such as diminutives (knižka  book-Dim, pesenka  song-Dim) and hypocorostics (Saša  Alexander, Nataša  Natalia). The paper is based on the analysis of the speech of parents from two longitudinal speech corpora of one girl and one boy from 2 to 3 years old. Their mothers demonstrated some differences in their use of derivatives concerning their preferences (mostly diminutives or hypocoristics – types или в tokens) and frequency. Most derivatives used by both mothers served as models for the important derivational processes: suffix rivalry with the same stem (hypocoristics) and adding one and the same suffixes to different stems (diminutive formation). Since the differences between literary Bulgarian and Russian in this sphere have been already described by several authors it would be interesting to compare the frequency of diminutives and hypocoristics in CDS for both languages.

Estimating infants’ language exposure: A comparison of random and volume sampling from daylong recordings collected in a bilingual community

In North America, the characteristics of a child’s language environment predict language outcomes. For example, differences in bilingual language exposure, exposure to electronic media, and exposure to child-directed speech (CDS) relate to children’s language growth. Recently, these predictors have been studied through the use of daylong recordings, followed by manual annotation of audio samples selected from these recordings. Using a dataset of daylong recordings collected from bilingually raised infants in the United States as an example, we ask whether two of the most commonly used sampling methods, random sampling and sampling based on high adult speech, differ from each other with regard to estimating the frequencies of specific language behaviors. Daylong recordings from 37 Spanish-English speaking families with infants between 4 and 22 months of age were analyzed. From each child’s recording, samples were extracted in two ways (at random/based on high adult speech) and then annotated for Language (Spanish/English/Mixed), CDS, Electronic Media, Social Context, Turn-Taking, and Infant Babbling. Correlation and agreement analyses were performed, in addition to paired sample t-tests, to assess how the choice of one or the other sampling method may affect the estimates. For most behaviors studied, correlation and agreement between the two sampling methods was high (Pearson r values between 0.79 and 0.99 for 16 of 17 measures; Intraclass Correlation Coefficient values between 0.78 and 0.99 for 13 of 17 measures). However, interesting between-sample differences also emerged: the degree of language mixing, the amount of CDS, and the number of conversational turns were all significantly higher when sampling was performed based on high adult speech compared to random sampling. By contrast, the presence of electronic media and one-on-one social contexts was higher when sampling was performed at random. We discuss advantages of choosing one sampling technique over the other, depending on the research question and variables at hand.

Attention-sensitive signalling by 7- to 20-month-old infants in a comparative perspective.

Attention-sensitive signalling is the pragmatic skill of signallers who adjust the modality of their communicative signals to their recipient's attention state. This study provides the first comprehensive evidence for its onset and development in 7-to 20-month-olds human infants, and underlines its significance for language acquisition and evolutionary history. Mother-infant dyads (N = 30) were studied in naturalistic settings, sampled according to three developmental periods (in months); [7-10], [11-14], and [15-20]. Infant's signals were classified by dominant perceptible sensory modality and proportions compared according to their mother's visual attention, infant-directed speech and tactile contact. Maternal visual attention and infant-directed speech were influential on the onset and steepness of infants' communicative adjustments. The ability to inhibit silent-visual signals towards visually inattentive mothers (unimodal adjustment) predated the ability to deploy audible-or-contact signals in this case (cross-modal adjustment). Maternal scaffolding of infant's early pragmatic skills through her infant-directed speech operates on the facilitation of infant's unimodal adjustment, the preference for oral over gestural signals, and the audio-visual combinations of signals. Additionally, breakdowns in maternal visual attention are associated with increased use of the audible-oral modality/channel. The evolutionary role of the sharing of attentional resources between parents and infants into the emergence of modern language is discussed.

Contribution of positive affect in infant directed speech: what do amplitude modulations patterns suggest?

Speech perception relies heavily on cortical entrainment of amplitude modulations in speech, which occur at different rates. Following a study by Leong et al. (2017) showing slower modulations have higher power than faster modulations in infant directed speech (IDS), we hypothesized that positive emotions in IDS might drive this pattern. Using the same analyses (spectral amplitude modulation phase hierarchy method and phase synchronization index (PSI) (Leong and Goswami, 2015)), we compared the power of isolated modulation rates (synchronous with neural oscillations) and the synchrony between them in IDS and adult directed speech (ADS), using English stimuli from Many Babies Consortium (Frank et al., 2020). We repeated the same analyses comparing happy and neutral ADS using stimuli of four native English speakers (Pell et al., 2009). Our analysis did not uncover significant power differences between IDS and ADS. However, it revealed happy ADS has higher power at slower rates, with the reversed pattern for neutral ADS (p < 0.001). PSI was higher for two faster rates in neutral ADS (p < 0.0001), as reported by Leong et al. comparing IDS versus ADS. These findings reveal novel acoustic features of vocal emotions that might be important in attracting infant attention to IDS.

Gender-related variation in /s/ and /ʃ/ in child-directed speech

Previous research showed that 3-year-old children assigned male at birth begin to produce /s/ differently from children assigned female at birth (Munson, Koeppe & Lackas, 2022). This mirrors the differences in /s/ found between cisgender men and women in American English (e.g., Jongman, Wayland & Wong, 2000; Munson, McDonald, DeBoe, & White, 2006). The current study investigates whether children are exposed to the gender-marking /s/ variants through child-directed speech, a hypothesis suggested by Foulkes, Docherty, and Watt (2005). We collected speech samples from 36 mothers of children aged 2 to 3 years through a story-reading task. Mothers read a male-themed story and a female-themed story to their children. We also measured mothers’ attitude towards their children’s gendered behavior. Spectral characteristics of /s/ and /ʃ/ were measured. As there was no evidence that /ʃ/ marks gender, the acoustic characteristics of /ʃ/ is measured to control for the potential influence of anatomical variation on fricative acoustics. Analysis is ongoing, and will examine whether the acoustic characteristics of /s/ in male- and female-themed stories resemble the male- and female-typed /s/ variants found in previous studies. The results of this study will inform models of the development of gendered speech in children.

Computational Modeling of the Segmentation of Sentence Stimuli From an Infant Word-Finding Study.

Computational models of infant word-finding typically operate over transcriptions of infant-directed speech corpora. It is now possible to test models of word segmentation on speech materials, rather than transcriptions of speech. We propose that such modeling efforts be conducted over the speech of the experimental stimuli used in studies measuring infants' capacity for learning from spoken sentences. Correspondence with infant outcomes in such experiments is an appropriate benchmark for models of infants. We demonstrate such an analysis by applying the DP-Parser model of Algayres and colleagues to auditory stimuli used in infant psycholinguistic experiments by Pelucchi and colleagues. The DP-Parser model takes speech as input, and creates multiple overlapping embeddings from each utterance. Prospective words are identified as clusters of similar embedded segments. This allows segmentation of each utterance into possible words, using a dynamic programming method that maximizes the frequency of constituent segments. We show that DP-Parse mimics American English learners' performance in extracting words from Italian sentences, favoring the segmentation of words with high syllabic transitional probability. This kind of computational analysis over actual stimuli from infant experiments may be helpful in tuning future models to match human performance.

Listening Preference for Child-Directed Speech Versus Time-Reversed Speech in Moderate-Preterm Infants Compared to Full-Term Infants.

The purpose of the present study was to examine whether there is a listening preference for child-directed speech (CDS) over backward speech in moderate-preterm infants (MPIs). Eighteen MPIs of gestational age of 32.0 weeks (range: 32-34.06 weeks), chronological age of 8.09 months, and maturation age of 6.48 months served as the experimental group. The two control groups consisted of a total of 36 infants-20 full-term infants matched for chronological age and 16 full-term infants matched for maturation age. The infants were tested using the central fixation procedure and were presented with 16 trials of CDS and backward speech. A follow-up was conducted 5 years after the initial experiment using a developmental and a five-item parent questionnaire. MPIs did not demonstrate a preference for CDS over backward speech, whereas both control groups demonstrated a listening preference for CDS over backward speech. MPIs showed a delayed use of first words and word combinations and lower scores on the five-item questionnaire compared to term infants. Twelve MPIs (67%) did not demonstrate a preference for CDS over backward speech. Four of them (33%) were later diagnosed with neurodevelopmental disorders. The lack of preference for CDS over backward speech in the MPIs group suggests delayed developmental pattern of speech processing compared to full-term peers. Delays in neurological maturation as well as listening experience in an unregulated environment outside the uterus during a sensitive period of brain development may affect the recognition of phonological and prosodic patterns that support listening preference for speech over backward speech.

Infant‐directed communication in Tanna, Vanuatu and Vancouver, Canada

AbstractIt is known that infant‐directed speech (IDS) plays a key role in language development. Previous research, however, has also identified significant variability across societies in terms of how often IDS occurs. For example, some studies report very little IDS in non‐western, small‐scale societies – including children growing up in small‐scale societies in Tanna, Vanuatu. This is surprising given that IDS is widely assumed as a common feature of human caregiving based on research conducted in urbanised populations which are more well‐studied. Here, we propose that IDS is only one of a suite of important caregiving behaviours that are produced during interactions with infants, which may vary by culture, perhaps being replaced by other, non‐verbal infant‐directed behaviours (IDB). We will examine previously collected data consisting of 94 semi‐structured 10‐min video observations of caregivers and their 18–24 month‐old children in rural Tanna, Vanuatu and urban Vancouver, Canada to identify and compare the proportion of time caregivers spend engaging in IDS and IDB during these interactions, both within and between societies. We define IDS as caregiver speech or vocalisations during the interaction with the infant, and we define IDB as non‐verbal behaviours that are produced with the infant during the interaction. This study aims to take a step towards a more generalised understanding of language development in children, moving beyond the urban and western societies in which our understanding of development is currently based, and the predicted results will aid in recognising different developmental pathways within multi‐cultural communities.

The face behind the caring voice: A comparative study on facial prosodic features of dog-, infant- and adult-directed communication

Although it has been known for over 40 years that people tend to adopt similar communication styles with both infants and dogs, the visual component of infant-directed speech (motherese) has been overlooked in research. The aim of the current study was to investigate variations in visual prosodic features across different addressees (i.e. dogs, infants, and adults) and the intended goal of communication. Parents who were also dog owners interacted with their infant (6–18 m.o.), their family dog and their spouses as adult-directed control in three different, 1–2-minute-long scenarios: language tutoring, attention-getting, and fixed sentences. We comparatively analysed speakers’ (N=46; 23 females, Mage= 34.41 years, SD=4.41) facial expressions (i.e., happy, surprised, neutral) and emotional states (valence, arousal) across scenarios and conditions using Noldus FaceReader software. Results revealed a significant interaction effect of condition and situation. As expected, visual prosody was the least intense in the dog-directed condition, with language tutoring showing the lowest intensity. Fixed sentences, with lexical content intended for infants (i.e. nursery rhyme), exhibited consistently the highest intensity. Interestingly, adult-directed prosody toward spouses resembled infant-directed prosody more than expected. In summary, our results highlight disparities in the interpretation of facial expressions in both con- and interspecies communication. Despite the study’s limitations, it emphasizes the importance of ongoing visual prosody characterisation, inviting further clarification and reconsideration of the dynamics between the visual and acoustic aspects of motherese and dog-directed talk as well as the role of bonding between interactants. These insights underscore the benefits of comparative cognition involving canines.

How teachers emphasize their speech: gestures and self-repetitions during group interaction with toddlers

When interacting with young children, adults often self-repeat their own utterances that vary in sequences of adjacent utterances called variation sets (VS) (Küntay and Slobin 1996). These repetitions benefit children’s linguistic development because they emphasize form and meaning. This paper analyzes the use of VS during group interaction and from a multimodal point of view. Sixteen teachers were video-recorded during interaction with two-year-old children in Spanish nursery schools. Results show that the use of VS is particularly frequent in these settings and that they are typically combined with gestures. Teachers directed their VS more often to a group of children than to a single child, and those VS directed to the group were more often accompanied by gestures than the VS directed to individuals. The results also show the influence of group size on children’s responses. The study thus sheds new light on our understanding of child-directed speech (CDS), as well as the need to adapt the speech to single children during interaction in large groups.

Infant-Directed Speech to Preterm Infants during the First Year Postpartum: The Influence of Preterm Birth Weight and Maternal Parenting Stress

Premature birth can increase the level of parenting stress (PS), especially in the case of parents of high-risk infants (extremely low birth weight (ELBW) and very low birth weight (VLBW)). Though published research has explored how maternal PS influences early dyadic interactions, limited research has focused on infant-directed speech (IDS), and no studies have investigated the link between prematurity severity based on birth weight and maternal IDS. This study, involving 100 mother–infant dyads, categorized into 30 ELBW premature infants, 30 VLBW premature infants, and 40 full-term (FT) ones, examined the impact of preterm birth weight and maternal parenting stress on IDS features during early interactions at 3 and 9 months postpartum. Maternal input was assessed using the CHILDES system, while parenting stress was evaluated using the Parenting Stress Index-Short Form. The results revealed that high-risk conditions (ELBW preterm birth and high parenting stress) at 3 months were associated with reduced affect-salient speech and increased questioning. IDS functional patterns, specifically the proportion of affect-salient speech and questions, were influenced by both birth weight groups and parenting stress levels at 3 months but not at 9 months. These findings highlight the need to assess, within the context of prematurity, both birth weight and parenting stress in clinical practice, offering insights for developing interventions supporting positive parent–infant interactions and facilitating infant development.

Processing of visual stimuli following infant directed speech: Attention-guiding effects of unfamiliar speech.

This study investigates attention modulation as a function of infant directed (ID) versus adult directed (AD) speech in seven-month-old infants using electroencephalographic measures. In three experiments, infants were presented with either ID speech or AD speech as stimuli, followed by highly variable images of inanimate objects as targets. In Experiment 1 (N=18), images were preceded by ID or AD speech with semantic content ("Look here"). Contrary to hypothesis, targets preceded by AD speech elicited increased amplitude of the Negative central (Nc) component compared to targets preceded by ID speech, indicating increased attention. Experiment 2 (N=23) explored whether ID versus AD speech influences attention allocation also without semantic content. The same targets were either preceded by human voice sounds without semantic content ("Uh-Ah") following the prosody of either ID or AD speech register. No differences in attention allocation or object processing were observed. Experiment 3 (N=18) contrasted ID speech with and without semantic content and found enhanced attention allocation following stimuli without semantic content, but increased object processing following stimuli with semantic content. Overall, the effects observed here are consistent with the idea that less familiar speech stimuli increase attention for subsequent objects. Semantic content of stimuli increased the depth of object processing in 7-month-olds.

Quantifying events or entities?—A corpus-based study of universal quantifiers in early child English and child-directed speech

The acquisition of quantifiers is a central topic in cognitive science. The present study investigated the emergence, frequency, and non-target-like production of the universal quantifiers all, every, and each in child English from a linguistic perspective, based on the data from longitudinal naturalistic observation of 10 English-speaking children and their caregivers. We found that the use of these quantifiers as adverbs or in adverbials generally appeared earlier, and was more frequent, than their use as (pre)determiners in early child English. We also found that input frequency exerts a great influence on some aspects of the acquisition of universal quantifiers, for example, the frequency of the predeterminer all, but there are still some patterns that cannot be explained by mere input frequency, such as children’s initial preference for using universal quantifiers in A(dverbial)-quantification and their non-target forms. Their initial overreliance on A-quantification may be explained by event quantification being cognitively less demanding than entity quantification, and their non-target productions likely result from their developing grammatical systems. We argue that the acquisition of universal quantifiers involves multiple factors, such as cognitive complexity, children’s developing grammatical systems, and input frequency, interacting with each other.

Baby Talk

Baby Talk

Korean Mothers’ Speech to Young Children with Cochlear Implants in Parent-Child Interaction

Objectives: Infant-directed speech is the particular form of spontaneous speech observed in interactions between parents and their young children. There are reasons to believe that infant-directed speech may help to make language acquisition easier for young children. Thus, this study investigates the effects of cochlear implantation on mothers’ speech to their young children.Methods: Fourteen children with cochlear implants (CIs) and 14 agematched children with normal hearing (NH), aged 12 to 35 months, participated in this study. We recorded mothers’ utterances through a parent-child interaction task. Mothers’ speech features such as fundamental frequency, utterance length, speech rate, and pause duration were measured across speech samples.Results: There were no significant differences between the CI and NH groups in fundamental frequency, utterance length, and pause duration variables. However, the speech of mothers in the CI group was significantly slower than that of the NH group.Conclusion: Mothers used typical infant-directed speech styles when speaking to their children with CIs. Additionally, mothers of the CI group tended to speak more slowly than mothers of the NH group in the parent-child interactions. Given that the language skills of children with CIs are significantly lower than those of children with NH in this study, mothers of the CI group may speak to their children at a slower rate than those of the NH group to provide their linguistic input more efficiently. These findings suggest that children with CIs are exposed to infant-directed speech with similar acoustic qualities as children with NH.

Ką lemia asimetrija: turkų kalbos kreipiniai bendraujant su naminiais gyvūnais, kūdikiais ir vaikais

Terms of address in Turkish spontaneous pet-, infant-, and child-directed speech were compared in terms of the proportion of diminutive and hypocoristic morphemes attached to various types of bases. The goal of the study was to see whether there was any difference in their distribution in different addressee groups that could be attributed to the asymmetrical communication in pet-directed speech. The results showed that, in Turkish, a language poor in diminutives and hypocoristics, the asymmetry is not observed in the distribution of diminutive and hypocoristic forms. It is observed, however, in the morphopragmatic expression of endearment in general that included the possessive morphology, which seemed to be an alternative form used instead of diminutives and hypocoristics or along with them.

Būdvardiškųjų žodžių derinimo ryšio įsisavinimas dvikalbystės sąlygomis

While studies on the acquisition of adjective agreement in the Lithuanian language are scarce, some research indicates that children face challenges in understanding morphosyntactic relationships, leading to errors in the use of adjectives and nouns in agreement. Consequently, children may switch less common inflections to more common ones, select declension paradigms based on analogy to other words, and exhibit errors in the grammatical category of gender. The present study investigates adjective agreement in bilingual children. Thirty-five bilingual children residing outside Lithuania completed a task based on a corpus of children’s and child-directed speech. The experimental task aimed to capture the diversity of adjective and noun paradigms. Test choices included, alongside the correct one, a paradigm error (a different paradigm inflection), a number error (a different number in the target paradigm), and a gender error (a different gender in the target paradigm). Results reveal that bilingual children encounter the most difficulty with agreement due to inflectional diversity, involving changes in inflection from unproductive to productive paradigms and copying noun inflections. Agreement errors in gender and number are also associated with paradigm diversity.

“It's not just what we say or do, but how we say and do it”

Infant-directed speech (IDS) and infant-directed actions (IDA) represent specific behavioural modifications of adults when they communicate with infants and young children. Infant-directed modifications (IDMs) have specific behavioural representations marked by high positive affection, greater expressiveness, simplification, and increased repetition. Both IDS and IDA appear as part of the same larger behavioural system of IDMs. However, so far, studies have analysed the features and functions of these behaviours separately. Compared to adult-directed speech, IDS is characterised by longer pauses, a slower tempo, more prosodic repetition, higher fundamental frequency, longer vowels, repetitive intonation structures, and greater melodiousness. In IDA, compared to adult-directed actions, the amplitude of movements, simplification, and number of repetitions tend to increase as the distance between communication partners decrease. In this review, we draw a parallel between IDS and IDA to show that adults change both their speech and actions in similar ways and that both actions and speech change depending on the infant’s age and/or developmental stage. We discuss possible (biological) mechanisms that elicit the use of IDS and IDA and argue that this specific type of adult behaviour has a unique impact on how infants perceive and process information. Insights on biological, behavioural, and functional aspects of IDMs could provide a new perspective on the importance of early interactions and knowledge acquisition in both typically developing children and those with developmental disorders.