Fathers' unmodulated prosody in child-directed speech.

Mothers and fathers modify prosodic characteristics of child-directed speech relative to adult-directed speech. Evidence suggests that mothers and fathers may differ in how they use child-directed speech as communicative partners. Thus, fathers create communicative challenges during father-child interaction that facilitate the child's adaptation to a wider potential range of interlocutors. In this paper, speech production differences are examined between mothers and fathers in child-directed speech to toddlers as compared to adult-directed speech. Using a longitudinal, large-scale design of audio recordings in naturalistic environments and automatic speech processing techniques, it was found that mothers, but not fathers, increased their fundamental frequency when addressing their toddlers. The results suggest that fathers do not modulate the prosody of their speech in the same way as mothers when communicating with their toddlers. Findings have implications for emotional and communicative practices of fathers compared to mothers and the differential role each plays in child development.

Effect of telepractice on pediatric cochlear implant users and provider vowel space: A preliminary report.

Clear speaking styles are goal-oriented modifications in which talkers adapt acoustic-phonetic characteristics of speech to compensate for communication challenges. Do children with hearing loss and a clinical provider modify speech characteristics during telepractice to adjust for remote communication? The study examined the effect of telepractice (tele-) on vowel production in seven (mean age 4:11 years, SD 1:2 years) children with cochlear implants (CIs) and a provider. The first (F1) and second (F2) formant frequencies of /i/, /ɑ/, and /u/ vowels were measured in child and provider speech during one in-person and one tele-speech-language intervention, order counterbalanced. Child and provider vowel space areas (VSA) were calculated. The results demonstrated an increase in F2 formant frequency for /i/ vowel in child and provider speech and an increase in F1 formant frequency for /ɑ/ vowel in the provider speech during tele- compared to in-person intervention. An expansion of VSA was found in child and provider speech in tele- compared to in-person intervention. In children, the earlier age of CI activation was associated with larger VSA in both tele- and in-person intervention. The results suggest that the children and the provider adjust vowel articulation in response to remote communication during telepractice.

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.

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.

Vocal imitation between mothers and their children with cochlear implants.

To better explain variation in language acquisition in children with hearing loss, this study examined vocal (e.g., vocalization) and lexical (e.g., word) imitation in spontaneous interactions between mothers and children with 12 months of hearing experience using their cochlear implants (n = 12; mean age 27.9 months). Hearing children in two control groups were matched to children with cochlear implants, either by child chronological age (n = 12; mean age = 27.4 months) or by child hearing experience (n = 12; mean age 12 months). All three groups of mother-child dyads were audio-recorded playing together. Mothers and children in all groups imitated their partners' vocalization and word utterances; however, the cochlear implant and hearing experience-matched groups produced fewer word imitations than the age-matched group. The frequency of preceding child vocalization or word production predicted maternal imitation type (vocalization or word); however, frequency of maternal vocalization predicted child vocalization imitation only. The results showed that child hearing experience affected imitation in both communication partners.

Vocal Turn-Taking Between Mothers and Their Children With Cochlear Implants.

OBJECTIVES: The primary objective of the study was to examine the occurrence and temporal structure of vocal turn-taking during spontaneous interactions between mothers and their children with cochlear implants (CI) over the first year after cochlear implantation as compared with interactions between mothers and children with normal hearing (NH). DESIGN: Mothers' unstructured play sessions with children with CI (n = 12) were recorded at 2 time points, 3 months (mean age 18.3 months) and 9 months (mean age 27.5 months) post-CI. A separate control group of mothers with age-matched hearing children (n = 12) was recorded at the same 2 time points. Five types of events were coded: mother and child vocalizations, vocalizations including speech overlap, and between- and within-speaker pauses. We analyzed the proportion of child and mother vocalizations involved in turn-taking, the temporal structure of turn-taking, and the temporal reciprocity of turn-taking using proportions of simultaneous speech and the duration of between- and within-speaker pauses. RESULTS: The CI group produced a significantly smaller proportion of vocalizations in turn-taking than the NH group at the first session; however, CI children's proportion of vocalizations in turn-taking increased over time. There was a significantly larger proportion of simultaneous speech in the CI compared with the NH group at the first session. The CI group produced longer between-speaker pauses as compared with those in the NH group at the first session with mothers decreasing the duration of between-speaker pauses over time. NH infants and mothers in both groups produced longer within- than between-speaker pauses but CI infants demonstrated the opposite pattern. In addition, the duration of mothers' between-speaker pauses (CI and NH) was predicted by the duration of the infants' between-speaker pauses. CONCLUSIONS: Vocal turn-taking and timing in both members of the dyad, the mother and infant, were sensitive to the experiential effects of child hearing loss and remediation with CI. Child hearing status affected dyad-specific coordination in the timing of responses between mothers and their children.

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.

Phonetic modification of vowel space in storybook speech to infants up to 2 years of age.

PURPOSE: A large body of literature has indicated vowel space area expansion in infant-directed (ID) speech compared with adult-directed (AD) speech, which may promote language acquisition. The current study tested whether this expansion occurs in storybook speech read to infants at various points during their first 2 years of life. METHOD: In 2 studies, mothers read a storybook containing target vowels in ID and AD speech conditions. Study 1 was longitudinal, with 11 mothers recorded when their infants were 3, 6, and 9 months old. Study 2 was cross-sectional, with 48 mothers recorded when their infants were 3, 9, 13, or 20 months old (n=12 per group). The 1st and 2nd formants of vowels /i/, /ɑ/, and /u/ were measured, and vowel space area and dispersion were calculated. RESULTS: Across both studies, 1st and/or 2nd formant frequencies shifted systematically for /i/ and /u/ vowels in ID compared with AD speech. No difference in vowel space area or dispersion was found. CONCLUSIONS: The results suggest that a variety of communication and situational factors may affect phonetic modifications in ID speech, but that vowel space characteristics in speech to infants stay consistent across the first 2 years of life.

Affective Properties of Mothers' Speech to Infants With Hearing Impairment and Cochlear Implants.

PURPOSE: The affective properties of infant-directed speech influence the attention of infants with normal hearing to speech sounds. This study explored the affective quality of maternal speech to infants with hearing impairment (HI) during the 1st year after cochlear implantation as compared to speech to infants with normal hearing. METHOD: Mothers of infants with HI and mothers of infants with normal hearing matched by age (NH-AM) or hearing experience (NH-EM) were recorded playing with their infants during 3 sessions over a 12-month period. Speech samples of 25 s were low-pass filtered, leaving intonation but not speech information intact. Sixty adults rated the stimuli along 5 scales: positive/negative affect and intention to express affection, to encourage attention, to comfort/soothe, and to direct behavior. RESULTS: Low-pass filtered speech to HI and NH-EM groups was rated as more positive, affective, and comforting compared with the such speech to the NH-AM group. Speech to infants with HI and with NH-AM was rated as more directive than speech to the NH-EM group. Mothers decreased affective qualities in speech to all infants but increased directive qualities in speech to infants with NH-EM over time. CONCLUSIONS: Mothers fine-tune communicative intent in speech to their infant's developmental stage. They adjust affective qualities to infants' hearing experience rather than to chronological age but adjust directive qualities of speech to the chronological age of their infants.

Age-related changes in prosodic features of maternal speech to prelingually deaf infants with cochlear implants.

This study investigated prosodic and structural characteristics of infant-directed speech to hearing-impaired infants as they gain hearing experience with a cochlear implant over a 12-month period of time. Mothers were recorded during a play interaction with their HI infants (N = 27, mean age 18.4 months) at 3, 6, and 12 months post-implantation. Two separate control groups of mothers with age-matched normal-hearing infants (NH-AM) (N = 21, mean age 18.1 months) and hearing experience-matched normal-hearing infants (NH-EM) (N = 24, mean age 3.1 months) were recorded at three testing sessions. Mothers produced less exaggerated pitch characteristics, a larger number of syllables per utterance, and faster speaking rate when interacting with NH-AM as compared to HI infants. Mothers also produced more syllables and demonstrated a trend suggesting faster speaking rate in speech to NH-EM relative to HI infants. Age-related modifications included decreased pitch standard deviation and increased number of syllables in speech to NH-AM infants and increased number of syllables in speech to HI and NH-EM infants across the 12-month period. These results suggest that mothers are sensitive to the hearing status of their infants and modify characteristics of infant-direct speech over time.

Effects of deafness on acoustic characteristics of American English tense/lax vowels in maternal speech to infants.

Recent studies have demonstrated that mothers exaggerate phonetic properties of infant-directed (ID) speech. However, these studies focused on a single acoustic dimension (frequency), whereas speech sounds are composed of multiple acoustic cues. Moreover, little is known about how mothers adjust phonetic properties of speech to children with hearing loss. This study examined mothers' production of frequency and duration cues to the American English tense/lax vowel contrast in speech to profoundly deaf (N = 14) and normal-hearing (N = 14) infants, and to an adult experimenter. First and second formant frequencies and vowel duration of tense (/i/, /u/) and lax (/I/, /ʊ/) vowels were measured. Results demonstrated that for both infant groups mothers hyperarticulated the acoustic vowel space and increased vowel duration in ID speech relative to adult-directed speech. Mean F2 values were decreased for the /u/ vowel and increased for the /I/ vowel, and vowel duration was longer for the /i/, /u/, and /I/ vowels in ID speech. However, neither acoustic cue differed in speech to hearing-impaired or normal-hearing infants. These results suggest that both formant frequencies and vowel duration that differentiate American English tense/lx vowel contrasts are modified in ID speech regardless of the hearing status of the addressee.

The effects of age and infant hearing status on maternal use of prosodic cues for clause boundaries in speech.

PURPOSE: The present study examined the effects of age and hearing status of a child on maternal use of pitch change, preboundary vowel lengthening, and pause duration, all of which are prosodic cues correlated with clause boundaries in infant-directed speech. METHOD: Mothers' speech to infants with normal hearing (NH; n = 18), infants who are profoundly deaf with a cochlear implant (HI; n = 9), and an adult experimenter were recorded at 2 time periods separated by 6 months. NH infants were matched to HI infants by chronological age or hearing experience. Fundamental frequency of pre- and postboundary vowels, vowel duration, and pause duration between utterances was measured. RESULTS: Results demonstrated that mothers (a) exaggerated prosodic characteristics in infant-directed speech regardless of infants' hearing status; (b) tailored preboundary vowel lengthening to infants' hearing experience rather than to chronological age; and (c) decreased exaggeration of pause duration over time. CONCLUSIONS: The results suggest that acoustic cues correlated with clause boundaries are available in maternal speech to HI infants. Their exaggeration relative to adult-directed speech suggests that mothers' use of infant-directed speech is a natural behavior regardless of infant hearing status. Finally, mothers modify speech prosody according to their children's age and hearing experience.

The role of selective attention in the acquisition of English tense and lax vowels by native Spanish listeners: comparison of three training methods.

This study investigates the role of two processes, cue enhancement (learning to attend to acoustic cues which characterize a speech contrast for native listeners) and cue inhibition (learning to ignore cues that do not), in the acquisition of the American English tense and lax ([i] vs.[I]) vowels by native Spanish listeners. This contrast is acoustically distinguished by both vowel spectrum and duration. However, while native English listeners rely primarily on spectrum, inexperienced Spanish listeners tend to rely exclusively on duration. Twenty-nine native Spanish listeners, initially reliant on vowel duration, received either enhancement training, inhibition training, or training with a natural cue distribution. Results demonstrated that reliance on spectrum properties increased over baseline for all three groups. However, inhibitory training was more effective relative to enhancement training and both inhibitory and enhancement training were more effective relative to natural distribution training in decreasing listeners' attention to duration. These results suggest that phonetic learning may involve two distinct cognitive processes, cue enhancement and cue inhibition, that function to shift selective attention between separable acoustic dimensions. Moreover, cue-specific training (whether enhancing or inhibitory) appears to be more effective for the acquisition of second language speech contrasts.

Analysis of categorical response data: use logistic regression rather than endpoint-difference scores or discriminant analysis.

Example of a typical second-language (L2) speech perception experiment: Synthetic vowel stimuli from a two-dimensional grid of points in which acoustic properties vary systematically in duration and spectral properties are classified as English /i/ or /I/ by L2-English listeners. In a number of studies, the data from such experiments have been analyzed using endpoint-difference scores or discriminant analysis. The current letter describes theoretical problems inherent in the first procedure in general, and in the application of the second procedure to data of this type in particular. Logistic regression is proposed as an alternative, which does not suffer from these problems.

The relationship between native allophonic experience with vowel duration and perception of the English tense/lax vowel contrast by Spanish and Russian listeners.

Two studies explored the role of native language use of an acoustic cue, vowel duration, in both native and non-native contexts in order to test the hypothesis that non-native listeners' reliance on vowel duration instead of vowel quality to distinguish the English tense/lax vowel contrast could be explained by the role of duration as a cue in native phonological contrasts. In the first experiment, native Russian, Spanish, and American English listeners identified stimuli from a beat/bit continuum varying in nine perceptually equal spectral and duration steps. English listeners relied predominantly on spectrum, but showed some reliance on duration. Russian and Spanish speakers relied entirely on duration. In the second experiment, three tests examined listeners' use of vowel duration in native contrasts. Duration was equally important for the perception of lexical stress for all three groups. However, English listeners relied more on duration as a cue to postvocalic consonant voicing than did native Spanish or Russian listeners, and Spanish listeners relied on duration more than did Russian listeners. Results suggest that, although allophonic experience may contribute to cross-language perceptual patterns, other factors such as the application of statistical learning mechanisms and the influence of language-independent psychoacoustic proclivities cannot be ruled out.