Vocal Development Research Articles

Towards an integrated view of vocal development.

Vocal development is usually studied from the perspective of neuroscience. In this issue, Zhang and Ghazanfar propose a way in which body growth might condition the process. They study the vocalizations of marmoset infants with a wide range of techniques that include computational models and experiments that mimic growth reversal. Their results suggest that the qualitative changes that occur during development are rooted in the nonlinear interaction between the nervous system and the biomechanics involved in respiration. This work illustrates how an integrative approach enriches our understanding of behavior.

A Case Study on Vocal Aerobic Treatment Voice Therapy Development and Application for Classical Singers

A Case Study on Vocal Aerobic Treatment Voice Therapy Development and Application for Classical Singers

Autonomous Discovery of Motor Constraints in an Intrinsically Motivated Vocal Learner

This paper introduces new results on the modeling of early vocal development using artificial intelligent cognitive architectures and a simulated vocal tract. The problem is addressed using intrinsically motivated learning algorithms for autonomous sensorimotor exploration, a kind of algorithm belonging to the active learning architectures family. The artificial agent is able to autonomously select goals to explore its own sensorimotor system in regions, where its competence to execute intended goals is improved. We propose to include a somatosensory system to provide a proprioceptive feedback signal to reinforce learning through the autonomous discovery of motor constraints. Constraints are represented by a somatosensory model which is unknown beforehand to the learner. Both the sensorimotor and somatosensory system are modeled using Gaussian mixture models. We argue that using an architecture which includes a somatosensory model would reduce redundancy in the sensorimotor model and drive the learning process more efficiently than algorithms taking into account only auditory feedback. The role of this proposed system is to predict whether an undesired collision within the vocal tract under a certain motor configuration is likely to occur. Thus, compromised motor configurations are rejected, guaranteeing that the agent is less prone to violate its own constraints.

A new measure of child vocal reciprocity in children with autism spectrum disorder.

Children and adults often engage in back-and-forth vocal exchanges. The extent to which they do so is believed to support children's early speech and language development. Two studies tested a new measure of child vocal reciprocity using computer-generated and real-life vocal samples of young children with autism collected in natural settings. The results provide initial evidence of accuracy, test-retest reliability, and validity of the new measure of child vocal reciprocity. A sound measure of children's vocal reciprocity might improve our ability to predict which children are on track to develop useful speech and/or are most likely to respond to language intervention. A free, publicly-available software program and manuals are provided.

Physical growth drives vocal sequence development in marmoset infants

The vocal sequences of marmosets exhibit many drastic changes during infancy. One of the most pronounced of these is the gradual convergence from a variety of call types in the undirected context to long distance contact calls (aka phee calls). We conjecture that such change is attributed to the interplay between the neural fluctuation and the biomechanics of the developing vocal periphery. To explore such possibility, we first quantitatively characterize vocal sequences and correlate them with animal momentary arousal levels. Based on this, we show that the diversity of respiratory and laryngeal patterns, as well as the commonly produced sequence transitions, can be generated via simple coupled oscillators with a low-dimensional input. In addition, the model predicts that as the respiratory apparatus grows, not only does the oscillatory period increase, but also the proportions of call types become biased towards phee calls. We further empirically test this hypothesis by placing the marmoset infants in a helium-oxygen (heliox) environment where the much lighter air reduces vocal effort, simulating smaller lungs. Consistent with the model prediction, the heliox manipulation reduces phee call duration and increases the proportion of other call types.The vocal sequences of marmosets exhibit many drastic changes during infancy. One of the most pronounced of these is the gradual convergence from a variety of call types in the undirected context to long distance contact calls (aka phee calls). We conjecture that such change is attributed to the interplay between the neural fluctuation and the biomechanics of the developing vocal periphery. To explore such possibility, we first quantitatively characterize vocal sequences and correlate them with animal momentary arousal levels. Based on this, we show that the diversity of respiratory and laryngeal patterns, as well as the commonly produced sequence transitions, can be generated via simple coupled oscillators with a low-dimensional input. In addition, the model predicts that as the respiratory apparatus grows, not only does the oscillatory period increase, but also the proportions of call types become biased towards phee calls. We further empirically test this hypothesis by placing the marmoset infants in a...

Precise Motor Control Enables Rapid Flexibility in Vocal Behavior of Marmoset Monkeys

Investigating the evolution of human speech is difficult and controversial because human speech surpasses nonhuman primate vocal communication in scope and flexibility [1-3]. Monkey vocalizations have been assumed to be largely innate, highly affective, and stereotyped for over 50 years [4, 5]. Recently, this perception has dramatically changed. Current studies have revealed distinct learning mechanisms during vocal development [6-8] and vocal flexibility, allowing monkeys to cognitively control when [9, 10], where [11], and what to vocalize [10, 12, 13]. However, specific call features (e.g., duration, frequency) remain surprisingly robust and stable in adult monkeys, resulting in rather stereotyped and discrete call patterns [14]. Additionally, monkeys seem to be unable to modulate their acoustic call structure under reinforced conditions beyond natural constraints [15, 16]. Behavioral experiments have shown that monkeys can stop sequences of calls immediately after acoustic perturbation but cannot interrupt ongoing vocalizations, suggesting that calls consist of single impartible pulses [17, 18]. Using acoustic perturbation triggered by the vocal behavior itself and quantitative measures of resulting vocal adjustments, weshow that marmoset monkeys are capable ofproducing calls with durations beyond the naturalboundaries of their repertoire by interrupting ongoing vocalizations rapidly after perturbation onset. Our results indicate that marmosets are capable of interrupting vocalizations only at periodic time points throughout calls, further supported by the occurrence of periodically segmented phees. These ideas overturn decades-old concepts on primate vocal pattern generation, indicating that vocalizations do not consist of one discrete call pattern but are built of many sequentially uttered units, like human speech.

Vocal development through morphological computation.

The vocal behavior of infants changes dramatically during early life. Whether or not such a change results from the growth of the body during development—as opposed to solely neural changes—has rarely been investigated. In this study of vocal development in marmoset monkeys, we tested the putative causal relationship between bodily growth and vocal development. During the first two months of life, the spontaneous vocalizations of marmosets undergo (1) a gradual disappearance of context-inappropriate call types and (2) an elongation in the duration of context-appropriate contact calls. We hypothesized that both changes are the natural consequences of lung growth and do not require any changes at the neural level. To test this idea, we first present a central pattern generator model of marmoset vocal production to demonstrate that lung growth can affect the temporal and oscillatory dynamics of neural circuits via sensory feedback from the lungs. Lung growth qualitatively shifted vocal behavior in the direction observed in real marmoset monkey vocal development. We then empirically tested this hypothesis by placing the marmoset infants in a helium–oxygen (heliox) environment in which air is much lighter. This simulated a reversal in development by decreasing the effort required to respire, thus increasing the respiration rate (as though the lungs were smaller). The heliox manipulation increased the proportions of inappropriate call types and decreased the duration of contact calls, consistent with a brief reversal of vocal development. These results suggest that bodily growth alone can play a major role in shaping the development of vocal behavior.

Vocalization development in common marmosets for neurodegenerative translational modeling

ObjectivesIn order to facilitate the study of vocalizations in emerging genetic common marmoset models of neurodegenerative disorders, we aimed to analyze call-type changes across age in a translational research environment. We hypothesized that acoustic parameters of vocalizations would change with age, reflecting growth of the vocal apparatus and a maturation of control needed to make adult-like calls.MethodsNineteen developing common marmosets were longitudinally video- and audio-recorded between the ages of 1–149 days in a naturalistic setting without any vocalization elicitation protocol. Vocalizations were coded for call type (cry, tsik, trill, phee, and trill-phee) and analyzed for duration (sec), minimum and maximum frequency (Hz), and bandwidth (Hz). Mixed model linear regressions were performed to assess the effects of age on call parameters listed above for each call type.ResultsCries decreased in duration (P = 0.038), maximum frequency (P = 0.047), and bandwidth (P = 0.023) with age. Tsik calls decreased in duration (P = 0.002) and increased in minimum frequency (P = 0.004) and maximum frequency (P = 0.005) with age. Trill calls increased in duration (P = 0.003), and trillphee bandwidth (P = 0.031) decreased with age.DiscussionOur results demonstrate that development of common marmoset vocalizations is call type dependent and that changes in acoustic parameters can be detected without complex vocalization elicitation paradigms or specialized audio recording equipment. Thus, we demonstrate the feasibility of a naturalistic protocol to collect and objectively analyze marmoset vocalizations longitudinally. This approach may be useful for studying vocal communication deficits in genetic models of neurodegenerative disorders.

β-Catenin signaling is essential for mammalian larynx recanalization and the establishment of vocal fold progenitor cells.

Congenital laryngeal webs result from failure of vocal fold separation during development in utero Infants present with life-threatening respiratory problems at birth, and extensive lifelong difficulties in breathing and voicing. The molecular mechanisms that instruct vocal fold formation are rarely studied. Here, we show, for the first time, that conditional inactivation of the gene encoding β-catenin in the primitive laryngopharyngeal epithelium leads to failure in separation of the vocal folds, which approximates the gross phenotype of laryngeal webbing. These defects can be traced to a series of morphogenesis defects, including delayed fusion of the epithelial lamina and formation of the laryngeal cecum, failed separation of the larynx and esophagus with reduced and disorganized cartilages and muscles. Parallel to these morphogenesis defects, inactivation of β-catenin disrupts stratification of epithelial cells and establishment of p63+ basal progenitors. These findings provide the first line of evidence that links β-catenin function to the cell proliferation and progenitor establishment during larynx and vocal fold development.

Utterance Duration as It Relates to Communicative Variables in Infant Vocal Development.

We aimed to provide novel information on utterance duration as it relates to vocal type, facial affect, gaze direction, and age in the prelinguistic/early linguistic infant. Infant utterances were analyzed from longitudinal recordings of 15 infants at 8, 10, 12, 14, and 16 months of age. Utterance durations were measured and coded for vocal type (i.e., squeal, growl, raspberry, vowel, cry, laugh), facial affect (i.e., positive, negative, neutral), and gaze direction (i.e., to person, to mirror, or not directed). Of the 18,236 utterances analyzed, durations were typically shortest at 14 months of age and longest at 16 months of age. Statistically significant changes were observed in utterance durations across age for all variables of interest. Despite variation in duration of infant utterances, developmental patterns were observed. For these infants, utterance durations appear to become more consolidated later in development, after the 1st year of life. Indeed, 12 months is often noted as the typical age of onset for 1st words and might possibly be a point in time when utterance durations begin to show patterns across communicative variables.

Ontogeny of long-range vocalizations in a Neotropical fossorial rodent: the Anillaco Tuco-Tuco (Ctenomys sp.).

Tuco-tucos (Ctenomys spp.) are subterranean rodents that produce territorial, high intensity long-range vocalizations (LRVs) of broadband and low frequency that are essential for long-distance communication between individuals in different tunnel systems. Despite their importance, the development of LRVs remains poorly understood. In adult Anillaco Tuco-Tucos (Ctenomys sp.) the LRV is composed by two types of syllables (series and individual notes) that are repeated a variable number of times. We studied the development of the LRVs in eight juveniles of the Anillaco Tuco-Tuco ranging from 14–28 to 104–118 days after birth. We (1) tested whether the syllables followed any of three alternative developmental modes (retention of juvenile vocalizations, modification of juvenile precursors or de novo appearance in adults), (2) evaluated the development of structural and acoustic features of syllables, and (3) tested the prediction that juveniles should produce a greater proportion of atypical series in precursors of the LRV than adults, due to lack maturation and/or precise coupling of neuromuscular and anatomical structures. The LRV of the Anillaco Tuco-Tuco exhibited a mixed developmental mode: while series developed from juvenile precursors whose acoustic features gradually approached those of adults, individual notes appeared later in the ontogeny and de novo with acoustic features indistinguishable from those of adults. The number of series per vocalization increased through development and varied from one to 25 in juvenile males and from one to six in juvenile females. The structure of the most common series type (triad) did not exhibit ontogenetic changes and was present as such at the onset of the emission of vocalizations. On the contrary, acoustic features of juvenile triad notes changed with age in both sexes (duration 90% increased through development, while bandwidth 90% and peak frequency decreased). Furthermore, juveniles emitted a higher proportion of atypical series than adults (7.4% vs. 0.3%), as expected in the development of any complex behavior that requires practice to be mastered. The maturation of the LRV occurred well before the sexual maturation, presumably due to the protracted time needed to acquire or build a burrow system long before mating is possible. We propose that protracted vocal development is another component in the slow developmental strategy of Ctenomys and subterranean rodents in general.

Early development of vocal interaction rules in a duetting songbird.

Exchange of vocal signals is an important aspect of animal communication. Although birdsong is the premier model for understanding vocal development, the development of vocal interaction rules in birds and possible parallels to humans have been little studied. Many tropical songbirds engage in complex vocal interactions in the form of duets between mated pairs. In some species, duets show precise temporal coordination and follow rules (duet codes) governing which song type one bird uses to reply to each of the song types of its mate. We determined whether these duetting rules are acquired during early development in canebrake wrens. Results show that juveniles acquire a duet code by singing with a mated pair of adults and that juveniles gradually increase their fidelity to the code over time. Additionally, we found that juveniles exhibit poorer temporal coordination than adults and improve their coordination as time progresses. Human turn-taking, an analogous rule to temporal coordination, is learned during early development. We report that the ontogeny of vocal interaction rules in songbirds is analogous to that of human conversation rules.

Early Vocal Development in Autism Spectrum Disorder, Rett Syndrome, and Fragile X Syndrome: Insights from Studies using Retrospective Video Analysis.

This article provides an overview of studies assessing the early vocalisations of children with autism spectrum disorder (ASD), Rett syndrome (RTT), and fragile X syndrome (FXS) using retrospective video analysis (RVA) during the first two years of life. Electronic databases were systematically searched and a total of 23 studies were selected. These studies were then categorised according to whether children were later diagnosed with ASD (13 studies), RTT (8 studies), or FXS (2 studies), and then described in terms of (a) participant characteristics, (b) control group characteristics, (c) video footage, (d) behaviours analysed, and (e) main findings. This overview supports the use of RVA in analysing the early development of vocalisations in children later diagnosed with ASD, RTT or FXS, and provides an in-depth analysis of vocalisation presentation, complex vocalisation production, and the rate and/or frequency of vocalisation production across the three disorders. Implications are discussed in terms of extending crude vocal analyses to more precise methods that might provide more powerful means by which to discriminate between disorders during early development. A greater understanding of the early manifestation of these disorders may then lead to improvements in earlier detection.

Vocal Traditions: Miller Voice Method

Vocal Traditions is a series in the Voice and Speech Review that highlights historically important voice teachers and schools of thought in the world of vocal pedagogy. In this essay, Miller Voice Method (MVM) offers its overview, history, teaching style and philosophy, goals, and details on certification. The key features of MVM are explored including: active breath, the attention blueprint, athleticism, on-camera applications, and text transfusion. The essay discusses the importance of integration—how the methodology assists actors in bridging the gap between technique and application, and the vital connection between the philosophy of the work and the work itself. The essay also describes unique MVM offerings including a video series highlighting core exercises (found on its website), on-camera techniques for vocal diagnostic and development, personalized action plans, and perspectives that reprioritize the audience’s experience as a vital component to actor training.

The social functions of babbling: acoustic and contextual characteristics that facilitate maternal responsiveness.

What is the social function of babbling? An important function of prelinguistic vocalizing may be to elicit parental behavior in ways that facilitate the infant's own learning about speech and language. Infants use parental feedback to their babbling to learn new vocal forms, but the microstructure of parental responses to babbling has not been studied. To enable precise manipulation of the proximal infant cues that may influence maternal behavior, we used a playback paradigm to assess mothers' responsiveness to prerecorded audiovisual clips of unfamiliar infants' noncry prelinguistic vocalizations and actions. Acoustic characteristics and directedness of vocalizations were manipulated to test their efficacy in structuring social interactions. We also compared maternal responsiveness in the playback paradigm and in free play with their own infants. Maternal patterns of reactions to babbling were stable across both tasks. In the playback task, we found specific vocal cues, such as the degree of resonance and the transition timing of consonant-vowel syllables, predicted contingent maternal responding. Vocalizations directed at objects also facilitated increased responsiveness. The responses mothers exhibited, such as sensitive speech and vocal imitation, are known to facilitate vocal learning and development. Infants, by influencing the behavior of their caregivers with their babbling, create social interactions that facilitate their own communicative development.

In vivo implantation of a tissue engineered stem cell seeded hemi-laryngeal replacement maintains airway, phonation, and swallowing in pigs.

Laryngeal functional impairment relating to swallowing, vocalisation, and respiration can be life changing and devastating for patients. A tissue engineering approach to regenerating vocal folds would represent a significant advantage over current clinical practice. Porcine hemi-larynx were de-cellularised under negative pressure. The resultant acellular scaffold was seeded with human bone marrow derived mesenchymal stem cells and primary human epithelial cells. Seeded scaffolds were implanted orthotopically into a defect created in the thyroid cartilage in 8 pigs and monitored in vivo for 2months. In vivo assessments consisted of mucosal brushing and bronchoscopy at 1, 2, 4, and 8weeks post implantation followed by histological evaluation post termination. The implanted graft had no adverse effect on respiratory function in 6 of the 8 pigs; none of the pigs had problems with swallowing or vocalisation. Six out of the 8 animals survived to the planned termination date; 2 animals were terminated due to mild stenosis and deep tissue abscess formation, respectively. Human epithelial cells from mucosal brushings could only be identified at Weeks 1 and 4. The explanted tissue showed complete epithelialisation of the mucosal surface and the development of rudimentary vocal folds. However, there was no evidence of cartilage remodelling at the relatively early censor point. Single stage partial laryngeal replacement is a safe surgical procedure. Replacement with a tissue engineered laryngeal graft as a single procedure is surgically feasible and results in appropriate mucosal coverage and rudimentary vocal fold development.

Vocalizations of minimally verbal children with autism spectrum disorder across the school year.

Little is known about the language trajectories of minimally verbal school-aged children with autism spectrum disorders. The present investigation conducted observations across two elementary schools over an entire school year to analyze the vocal language development of nine minimally verbal children with autism spectrum disorder between the ages of 6 and 10 years, and their educational service providers. A Language Environment Analysis™ device automatically recorded and disaggregated over 743 h of data on child vocalizations, and vocal interactions with adults. Vocalizations did not increase for eight of the nine participants, and conversational counts between participants and adults were near zero across the entire year. These results speak to the need for additional research examining language development and potential intervention strategies among minimally verbal children with autism spectrum disorder.

Ordinary Interactions Challenge Proposals That Maternal Verbal Responses Shape Infant Vocal Development.

This study tested proposals that maternal verbal responses shape infant vocal development, proposals based in part on evidence that infants modified their vocalizations to match mothers' experimentally manipulated vowel or consonant-vowel responses to most (i.e., 70%-80%) infant vocalizations. We tested the proposal in ordinary rather than experimentally manipulated interactions. Response-based proposals were tested in a cross-sectional study of 35 infants, ages 4 to 14 months, engaged in everyday interactions in their homes with their mothers using a standard set of toys and picture books. Mothers responded to 30% of infant vocalizations with vocal behaviors of their own, far fewer than experimentally manipulated response rates. Moreover, mothers produced comparatively few vowel and consonant-vowel models and responded to infants' vowel and consonant-vowel vocalizations in similar numbers. Infants showed little evidence of systematically modifying their vocal forms to match maternal responses in these interactions. Instead, consonant-vowel vocalizations increased significantly with infant age. Results obtained in ordinary interactions, rather than response manipulation, did not provide substantial support for response-based mechanisms of infant vocal development. Consistent with other research, however, consonant-vowel productions increased with infant age.

Longitudinal Study of Vocal Development in 9- to 18-Month-Old Children Acquiring Korean

배경 및 목적: 본 연구는 생후 9개월부터 18개월까지 일반 아동의 초기 발성의 유형별 비율 변화를 종단적으로 살펴보았다. 방법: 출생 전-중-후 특이사항이 없는 일반 아동 13명으로부터 9개월부터 18개월까지 3개월 간격으로 음성 샘플을 수집하였다. 아동의 음성 샘플을 발성 단위로 분절한 뒤에 음절구조 포함여부에 따라 크게 전 음절성 발성과 음절성...

Auditory isolation in rat pups and development of ultrasonic vocalization

Auditory isolation in rat pups and development of ultrasonic vocalization