Factors affecting consonant production accuracy in children with cochlear implants: Expressive vocabulary and maternal education.

BACKGROUND: Despite the ability of cochlear implants (CIs) to provide children with access to speech, there is considerable variability in spoken language outcomes. Research aimed at identifying factors influencing speech production accuracy is needed. AIMS: To characterize the consonant production accuracy of children with cochlear implants (CWCI) and an age-matched group of children with typical hearing (CWTH) and to explore several factors that potentially affect the ability of both groups to accurately produce consonants. METHODS & PROCEDURES: We administered the Bankson-Bernthal Test of Phonology (BBTOP) to a group of 25 CWCI (mean age = 4;9, SD = 1;6, range = 3;2-8;5) implanted prior to 30 months of age with a mean duration of implant usage of 3;6 and an age-matched group of 25 CWTH (mean age = 5;0, SD = 1;6, range = 3;1-8;6). The recorded results were transcribed, and the accuracy of the target consonants was determined. Expressive vocabulary size estimates were obtained from a language sample using the number of different words (NDW). A parent questionnaire provided information about maternal education, duration of CIs experience and other demographic characteristics of each child. OUTCOMES & RESULTS: The CWCI group demonstrated some similarities to, and some differences from, their hearing peers. The CWCI demonstrated poorer consonant production accuracy overall and in various phonetic categories and word positions. However, both groups produced initial consonants more accurately than final consonants. Whilst CWCI had poorer production accuracy than CWTH for all phonetic categories (stops, nasals, fricatives, affricates, liquids and glides and consonant clusters), both groups exhibited similar error patterns across categories. For CWCI, the factors most related to consonant production accuracy when considered individually were expressive vocabulary size, followed by duration of CI experience, chronological age, maternal education and gender. The combination of maternal education and vocabulary size resulted in the best model of consonant production accuracy for this group. For the CWTH, chronological age followed by vocabulary size were most related to consonant production accuracy. No combination of factors yielded an improved model for the CWTH. CONCLUSIONS & IMPLICATIONS: Whilst group differences in production accuracy between the CWCI and CWTH were found, the pattern of errors was similar for the two groups of children, suggesting that the children are at earlier stages of overall consonant production development. Although duration of CI experience was a significant covariate in a single-variable model of consonant production accuracy for CWCI, the best multivariate model of consonant production accuracy for these children was based on the combination of expressive vocabulary size and maternal education. WHAT THIS PAPER ADDS: What is already known on the subject Research has shown that a range of factors is associated with consonant production accuracy by CWCIs, including factors such as the age at implant, duration of implant use, gender, other language skills and maternal education. Despite numerous studies that have examined speech sound production in these children, most have explored a limited number of factors that might explain the variability in scores obtained. Research that examines the potential role of a range of child-related and environmental factors in the same children is needed to determine the predictive role of these factors in speech production outcomes. What this paper adds to the existing knowledge Whilst the consonant production accuracy was lower for the CWCIs than for their typically hearing peers, there were some similarities suggesting that these children are experiencing similar, but delayed, acquisition of consonant production skills to that of their hearing peers. Whilst several factors are predictive of consonant production accuracy in children with implants, vocabulary diversity and maternal education, an indirect measure of socio-economic status, were the best combined predictors of consonant production accuracy. What are the potential or actual clinical implications of this work? Understanding the factors that shape individual differences in CWCI speech production is important for effective clinical decision-making and intervention planning. The present findings point to two potentially important factors related to speech sound production beyond the duration of robust hearing in CWCI, namely, a lexical diversity and maternal education. This suggests that intervention is likely most efficient that addresses both vocabulary development and speech sound development together. The current findings further suggest the importance of parental involvement and commitment to spoken language development and the importance of receiving early and consistent intervention aimed both at skill development and parental efficacy.

Babbling in extremely premature infants at 12 months corrected age.

Babbling is an important precursor to speech in infancy, and deviations from the typical babbling development can predict later difficulties in speech, language, and communication. This cross-sectional study aimed to investigate babbling and early speech in Swedish extremely premature infants. Samples of babbling were collected from 20 extremely premature infants (EPT group) at the corrected age of 12 months. Data collection was home-based and consisted of an audio-video recording of each infant playing with a parent. Presence of canonical babbling (CB), and three oral stop variables distinctive of typical babbling, and consonant inventory were assessed. The assessment was performed during a standardised observation of babbling. Data from the EPT group were compared to previously collected data of a reference group of 20 10-month-old infants without known medical diagnoses. The results showed that the EPT group had a lower proportion of infants producing CB, and that they used a significantly smaller consonant inventory compared to the reference group. Although not statistically significant, oral stops were less frequently found in the EPT group. The findings of a restricted consonant inventory and low proportion of CB in the EPT group are not surprising considering that the group has been found to be at risk of speech and language delay in toddlerhood. Still, further research is needed to explore whether babbling at 12 months can predict speech and language skills at an older age in extremely premature infants.

Conspiring simplification strategies of [Obstruent+Liquid] clusters in a case study of child Greek: emergence of the marked.

This paper addresses the idiosyncratic cluster simplification patterns observed in a child with disordered phonological development, who is acquiring Greek. The child has mastered word-internal and word-final codas and clusters of reversed sonority. However, the child does not realise the target well-formed tautosyllabic [Obstruent+Liquid] clusters with rising sonority. The child's system requires a single onset with maximum sonority dispersion between the onset and the syllable nucleus. As a result, cluster simplification occurs, via reduction to the less sonorous Obstruent - the most prevalent reduction pattern cross-linguistically. However, at the same time, the grammar requires faithful realisation of the target segment number. This requirement is fulfiled through two distinct conspiring metathesis patterns, distributed complementarily, resulting in the realisation of marked structures. The patterns depend on the position of the cluster within the target word. In word internal position, a compensatory metathesis of the Liquid takes place in the preceding syllable coda. In word initial position, the Manner of Articulation of the metathesised Liquid is delinked, while its Coronal Place of Articulation is faithfully preserved, and is realised by default as a Coronal Sibilant [s]. The latter Sibilant is attached as an appendix to the syllable node at the word left-edge. We argue that, in the grammar of this child, there is a-synchronisation between the development of the prosodic word layer and the development of syllable layer. Specifically, a-synchronisation is evident in the development of the (branching) onset syllabic subconstituent.

Speech Categorization Reveals the Role of Early-Stage Temporal-Coherence Processing in Auditory Scene Analysis.

Temporal coherence of sound fluctuations across spectral channels is thought to aid auditory grouping and scene segregation. Although prior studies on the neural bases of temporal-coherence processing focused mostly on cortical contributions, neurophysiological evidence suggests that temporal-coherence-based scene analysis may start as early as the cochlear nucleus (i.e., the first auditory region supporting cross-channel processing over a wide frequency range). Accordingly, we hypothesized that aspects of temporal-coherence processing that could be realized in early auditory areas may shape speech understanding in noise. We then explored whether physiologically plausible computational models could account for results from a behavioral experiment that measured consonant categorization in different masking conditions. We tested whether within-channel masking of target-speech modulations predicted consonant confusions across the different conditions and whether predictions were improved by adding across-channel temporal-coherence processing mirroring the computations known to exist in the cochlear nucleus. Consonant confusions provide a rich characterization of error patterns in speech categorization, and are thus crucial for rigorously testing models of speech perception; however, to the best of our knowledge, they have not been used in prior studies of scene analysis. We find that within-channel modulation masking can reasonably account for category confusions, but that it fails when temporal fine structure cues are unavailable. However, the addition of across-channel temporal-coherence processing significantly improves confusion predictions across all tested conditions. Our results suggest that temporal-coherence processing strongly shapes speech understanding in noise and that physiological computations that exist early along the auditory pathway may contribute to this process.SIGNIFICANCE STATEMENT Temporal coherence of sound fluctuations across distinct frequency channels is thought to be important for auditory scene analysis. Prior studies on the neural bases of temporal-coherence processing focused mostly on cortical contributions, and it was unknown whether speech understanding in noise may be shaped by across-channel processing that exists in earlier auditory areas. Using physiologically plausible computational modeling to predict consonant confusions across different listening conditions, we find that across-channel temporal coherence contributes significantly to scene analysis and speech perception and that such processing may arise in the auditory pathway as early as the brainstem. By virtue of providing a richer characterization of error patterns not obtainable with just intelligibility scores, consonant confusions yield unique insight into scene analysis mechanisms.

Cross-cultural evaluation of learning and memory using a consonant-vowel-consonant trigram list.

OBJECTIVE: Word list-learning tasks are commonly used to evaluate auditory-verbal learning and memory. However, different frequencies of word usage, subtle meaning nuances, unique word phonology, and different preexisting associations among words make translation across languages difficult. We administered lists of consonant-vowel-consonant (CVC) nonword trigrams to independent American and Italian young adult samples. We evaluated whether an auditory list-learning task using CVC nonword trigrams instead of words could be applied cross-culturally to evaluate similar learning and associative memory processes. PARTICIPANTS AND METHODS: Seventy-five native English-speaking (USA) and 104 native Italian-speaking (Italy) university students were administered 15-item lists of CVC trigrams using the Rey Auditory Verbal Learning Test paradigm with five study-test trials, an interference trial, and short- and long-term delayed recall. Bayesian t tests and mixed-design ANOVAs contrasted the primary learning indexes across the two samples and biological sex. RESULTS: Performance was comparable between nationalities on all primary memory indices except the interference trial (List B), where the Italian group recalled approximately one item more than the American sample. For both nationalities, recall increased across the five learning trials and declined significantly on the postinterference trial, demonstrating susceptibility to retroactive interference. No effects of sex, age, vocabulary, or depressive symptoms were observed. CONCLUSIONS: Using lists of unfamiliar nonword CVC trigrams, Italian and American younger adults showed a similar performance pattern across immediate and delayed recall trials. Whereas word list-learning performance is typically affected by cultural, demographic, mood, and cognitive factors, this trigram list-learning task does not show such effects, demonstrating its utility for cross-cultural memory assessment.

Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: Speech proficiency at 10 years of age.

BACKGROUND & AIM: To assess consonant proficiency and velopharyngeal function in 10-year-old children born with unilateral cleft lip and palate (UCLP) within the Scandcleft project. METHODS & PROCEDURES: Three parallel group, randomized, clinical trials were undertaken as an international multicentre study by nine cleft teams in five countries. Three different surgical protocols for primary palate repair (Arm B-Lip and soft palate closure at 3-4 months, hard palate closure at 36 months, Arm C-Lip closure at 3-4 months, hard and soft palate closure at 12 months, and Arm D-Lip closure at 3-4 months combined with a single-layer closure of the hard palate using a vomer flap, soft palate closure at 12 months) were tested against a common procedure (Arm A-Lip and soft palate closure at 3-4 months followed by hard palate closure at 12 months) in the total cohort of 431 children born with a non-syndromic UCLP. Speech audio and video recordings of 399 children were available and perceptually analysed. Percentage of consonants correct (PCC) from a naming test, an overall rating of velopharyngeal competence (VPC) (VPC-Rate), and a composite measure (VPC-Sum) were reported. OUTCOMES & RESULTS: The mean levels of consonant proficiency (PCC score) in the trial arms were 86-92% and between 58% and 83% of the children had VPC (VPC-Sum). Only 50-73% of the participants had a consonant proficiency level with their peers. Girls performed better throughout. Long delay of the hard palate repair (Arm B) indicated lower PCC and simultaneous hard and soft palate closure higher (Arm C). However, the proportion of participants with primary VPC (not including velopharyngeal surgeries) was highest in Arm B (68%) and lowest in Arm C (47%). CONCLUSIONS & IMPLICATIONS: The speech outcome in terms of PCC and VPC was low across the trials. The different protocols had their pros and cons and there is no obvious evidence to recommend any of the protocols as superior. Aspects other than primary surgical method, such as time after velopharyngeal surgery, surgical experience, hearing level, language difficulties and speech therapy, need to be thoroughly reviewed for a better understanding of what has affected speech outcome at 10 years. WHAT THIS PAPER ADDS: What is already known on the subject Speech outcomes at 10 years of age in children treated for UCLP are sparse and contradictory. Previous studies have examined speech outcomes and the relationship with surgical intervention in 5-year-olds. What this study adds to the existing knowledge Speech outcomes based on standardized assessment in a large group of 10-year-old children born with UCLP and surgically treated according to different protocols are presented. While speech therapy had been provided, a large proportion of the children across treatment protocols still needed further speech therapy. What are the potential or actual clinical implications of this work? Aspects other than surgery and speech function might add to the understanding of what affects speech outcome. Effective speech therapy should be available for children in addition to primary surgical repair of the cleft and secondary surgeries if needed.

Vowel and consonant quantity in two Swiss German dialects and their corresponding varieties of Standard German: effects of region, age, and tempo.

The diglossic situation in German-speaking Switzerland entails that both an Alemannic dialect and a Swiss standard variety of German are spoken. One phonological property of both Alemannic and Swiss Standard German (SSG) is contrastive quantity not only in vowels but also in consonants, namely lenis and fortis. This study aims to compare vowel and plosive closure durations as well as articulation rate (AR) between Alemannic and SSG in the varieties spoken in a rural area of the canton of Lucerne (LU) and an urban area of the canton of Zurich (ZH). In addition to the segment durations, an additional measure of vowel-to-vowel + consonant duration (V/(V + C)) ratios is calculated in order to account for possible compensation between vowel and closure durations. Stimuli consisted of words containing different vowel-consonant (VC) combinations. The main differences found are longer segment durations in Alemannic compared to SSG, three phonetic vowel categories in Alemannic that differ between LU and ZH, three stable V/(V + C) ratio categories, and three phonetic consonant categories lenis, fortis, and extrafortis in both Alemannic and SSG. Most importantly, younger ZH speakers produced overall shorter closure durations, calling into question a possible reduction of consonant categories due to a contact to German Standard German (GSG).

Individual differences in attention control and the processing of phonological contrasts in a second language.

This study investigated attention control in L2 phonological processing from a cognitive individual differences perspective, to determine its role in predicting phonological acquisition in adult L2 learning. Participants were 21 L1-Spanish learners of English, and 19 L1-English learners of Spanish. Attention control was measured through a novel speech-based attention-switching task. Phonological processing was assessed through a speeded ABX categorization task (perception) and a delayed sentence repetition task (production). Correlational analyses indicated that learners with more efficient attention switching skill and faster speed in correctly identifying the target phonetic features in the speech dimension under focus could perceptually discriminate L2 vowels at higher processing speed, but not at higher accuracy rates. Thus, attentional flexibility provided a processing advantage for difficult L2 contrasts but did not predict the extent to which precise representations for the target L2 vowels had been established. However, attention control was related to L2 learners' ability to distinguish the contrasting L2 vowels in production. In addition, L2 learners' accuracy in perceptually distinguishing between two contrasting vowels was significantly related to how much of a quality distinction between them they could make in production.

Child phonological responses to variegation in adult words: A cross-linguistic study.

Variegation - the presence of more than one supraglottal consonant per word - is a key challenge for children as they increase their expressive vocabulary toward the end of the single-word period. Here we consider the prosodic structures of target words and child forms in English, Finnish, French, Japanese and Mandarin to determine whether children learning these languages respond similarly to the challenge or instead differ in ways related to the phonological structure of the adult language. Based on proportional occurrence of each structure, we find that the word forms of children learning Mandarin and Japanese show more variegation than do those of children learning the European languages, although their target words do not; proportions of reduplication, consonant harmony and single-consonant words also differ by language. We conclude that experience with the structure of the language - and thus representation, as well as immature articulatory skills - shapes children's responses to variegation.

Disentangling Effects of Memory Storage and Inter-articulator Coordination on Generalization in Speech Motor Sequence Learning.

Generalization in motor control is the extent to which motor learning affects movements in situations different than those in which it originally occurred. Recent data on orofacial speech movements indicates that motor sequence learning generalizes to novel syllable sequences containing phonotactically illegal, but previously practiced, consonant clusters. Practicing an entire syllable, however, results in even larger performance gains compared to practicing just its clusters. These patterns of generalization could reflect language-general changes in phonological memory storage and/or inter-articulator coordination during motor sequence learning. To disentangle these factors, we conducted two experiments in which talkers intensively practiced producing novel syllables containing illegal onset and coda clusters over two consecutive days. During the practice phases of both experiments, we observed that, through repetition, talkers gradually produced the syllables with fewer errors, indicative of learning. After learning, talkers were tested for generalization to single syllables (Experiment 1) or syllable pairs (Experiment 2) that overlapped to varying degrees with the practiced syllables. Across both experiments, we found that performance improvements from practicing syllables with illegal clusters partially generalized to novel syllables that contained those clusters, but performance was more error prone if the clusters occurred in a different syllable position (onset versus coda) as in practice, demonstrating that inter-articulator coordination is contextually sensitive. Furthermore, changing the position of a cluster was found to be more deleterious to motor performance during the production of the second syllables in syllable pairs, which required talkers to store more phonological material in memory prior to articulation, compared to single syllables. This interaction effect reveals a complex interplay between memory storage and inter-articulator coordination on generalization in speech motor sequence learning.

Transcribing toddler vocalizations: comparison of a modified naturalistic listening approach with phonetic transcription.

Previous investigations have demonstrated that naturalistic listening in real time (NLRT) can be used reliability to assess prelinguistic vocalizations and is less time-consuming than phonetic transcription. The current investigation was performed to examine the correspondence of syllable and consonant information obtained using a modified naturalistic listening in real time (NLRT) methodology compared to broad phonetic transcription for 20 toddlers with repaired cleft palate. A forty-minute vocalization sample was obtained for each toddler. Two listeners listened to each recording independently and coded the number of syllables and consonant types produced by each toddler using NLRT. Each recording was phonetically transcribed by each listener 2 to 16 months following the NLRT analysis. High reliability was evident between the modified NSRT method and phonetic transcription for identification of both syllables and consonants. Differences were evident in the actual number of syllables and consonants identified between the two types of assessment across the 20 participants. Possible explanations for those differences are addressed. The results of this investigation indicate that the modified NLRT procedure is a reliable method for determining consonant/inventories of young children. It is less labor intensive than traditional phonetic transcription and may be useful clinically when documentation of early sound development is needed to support early intervention decisions.

Positional asymmetries in consonant production and intelligibility in dysarthric speech.

Consonant production errors are common in dysarthric speech, but not all consonants are affected to the same extent. Currently, only limited knowledge exists regarding whether different positional allophones are affected to varying degrees in dysarthric speech. The aim of this study was to investigate the effect of consonants' position-in-words on consonant production accuracy and their relevance to speech intelligibility. To this end, the percentage of correctly articulated consonants was analyzed with respect to position-in-words, manner of articulation, and speakers' overall intelligibility in dysarthric speech secondary to cerebral palsy. Results revealed that consonants were generally more accurate in initial positions than other positions, and when they were singletons rather than clusters. However, fricatives, a category commonly noted for frequent misarticulations, exhibited no significant positional effects, indicating that fricatives were affected to a similar degree across all word positions. In addition, positional asymmetry manifested to a greater degree as intelligibility decreased. Finally, the strength of the relationship between consonant production accuracy and intelligibility varied depending on positions-in-words, with strong correlations in the medial and final cluster positions but no significant correlation for fricatives in the initial and final singleton positions. The correlation was markedly low for the initial consonants, possibly due to the resistance of initial consonants to production errors. The positional asymmetry found in this study necessitates more research on non-initial consonants and clusters for their potential in improving consonant production and speech intelligibility as a part of dysarthria management.

Exploring word production in three-year-old monolingual French-speaking children.

There is a general need for more knowledge on the development of French phonology, and little information is currently available for typically developing French-speaking three-year-old children. This study took place in Belgium and explores the accuracy of speech production of 34 typically developing French-speaking children using a picture naming task. Measures of speech accuracy revealed lower performance than previously seen in the literature. We investigated speech accuracy across different phonological contexts in light of characteristics of target words that are known to have an influence on speech production, namely the condition of production (spontaneous vs. imitated), the length of the word (in number of syllables), syllable complexity (singleton vs. cluster) and positional complexity (onset vs. coda). Results indicate that the accuracy of words produced spontaneously did not differ from imitated words. The presence of consonant clusters in the target word was associated with lower performance on measures of Percentage of Consonants Correct and Whole Word Proximity for both 1- and 4-syllable words. Singleton codas were produced less accurately than onsets in 1-syllable words. Word-internal singleton codas were produced less accurately than final codas. In our sample, 1-syllable words showed surprisingly low levels of performance which we can explain by an over-representation of phonologically complex properties in the target words used in the present study. These results highlight the importance of assessing various aspects of phonological complexity in French speech tasks in order to detect developmental errors in typically developing children and, ultimately, help identify children with speech sound disorders.

Word-final complexity in speech sound intervention: two case studies.

In speech sound intervention, consonant clusters promote generalisation (i.e. improvement in untreated sounds and words), ostensibly due to their relative complexity compared to other phonological targets. However, our understanding of clusters as intervention targets is largely restricted to those in word-initial position (e.g. [fl-], flip). The present study extends available work to consider the effects of word-final consonant cluster targets (e.g. [-ks]). Phonologically complex word-final clusters may be morphologically simple (e.g. mix) or morphologically complex (e.g. packs, inflected with third-person singular) - yet this cross-domain complexity remains an understudied phenomenon. Presently, two case studies provide an initial investigation of word-final cluster intervention targets for children with phonologically based speech sound disorders. Intervention targets for both Anna (3;7 [years;months]) and David (4;1) featured the phonologically complex word-final cluster [-ks], with Anna's target being morphologically simple and David's being morphologically complex. Intervention was provided in 45-minute, individual sessions three times per week for a maximum of 18 sessions. Both children demonstrated high target accuracy by intervention's end. Following intervention, both children demonstrated progress in intelligibility and ability to produce word-final consonant clusters; David further demonstrated generalisation across multiple measures. Results are interpreted with consideration of individual differences and existing research on complexity in phonological intervention. Overall, present findings motivate continued research, as manipulation of word-final complexity allows for emphasis on a context that is relevant for children with speech sound disorders, for peers with difficulties in morphology (including word-final grammatical morphemes) and for the substantial proportion of children demonstrating weaknesses in both domains.

Spanish-learning infants switch from a vowel to a consonant bias during the first year of life.

The consonant bias is evidenced by a greater reliance on consonants over vowels in lexical processing. Although attested during adulthood for most Roman and Germanic languages (e.g., French, Italian, English, Dutch), evidence on its development suggests that the native input modulates its trajectory. French and Italian learners exhibit an early switch from a higher reliance on vowels at 5 and 6 months of age to a consonant bias by the end of the first year. This study investigated the developmental trajectory of this bias in a third Romance language unexplored so far-Spanish. In a central visual fixation procedure, infants aged 5, 8½, and 12 months were tested in a word recognition task. In Experiment 1, infants preferred listening to frequent words (e.g., leche, milk) over nonwords (e.g., machi) at all ages. Experiment 2 assessed infants' listening times to consonant and vowel alterations of the words used in Experiment 1. Here, 5-month-olds preferred listening to consonant alterations, whereas 12-month-olds preferred listening to vowel alterations, suggesting that 5-month-olds' recognition performance was more affected by a vowel alteration (e.g., leche →lache), whereas 12-month-olds' recognition performance was more affected by a consonant alteration (e.g., leche →keche). These findings replicate previous findings in Italian and French and generalize them to a third Romance language (Spanish). As such, they support the idea that specific factors common to Romance languages might be driving an early consonant bias in lexical processing.

Speech perception in noise in children with dyslexia: Does speech sound disorder matter?

The aim of this observational cohort study with a control group is to compare consonant perception skills in quiet and in noise in children with typical language and learning development and in children with dyslexia, with and without Speech Sound Disorder (SSD). Three groups were included: A control group of twenty children with normal reading abilities and typical language development, twelve children with dyslexia and typical language development and thirteen children with dyslexia and SSD. All subjects received a consonant recognition test in three different listening conditions (quiet, + 10 and 0 Signal-to-Noise Ratio). In all test conditions, children with dyslexia and SSD had significantly lower consonant recognition scores than the control group and the children with dyslexia and typical language development (p < .0001). The poorer performances observed in children with dyslexia and SSD may be explained by impaired phonological processing underlying both conditions.

Speech production in Mandarin-speaking children with cochlear implants: a systematic review.

OBJECTIVE: This study aimed to systematically review and critically appraise the literature describing the phonetic characteristics and accuracy of the consonants, vowels and tones produced by Mandarin-speaking children with cochlear implants (CIs). DESIGN: The protocol in this review was designed in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. EBSCOhost, PubMed, Scopus, PsycINFO, ProQuest Central databases were searched for relevant articles which met the inclusion criteria. STUDY SAMPLE: A total of 18 journal papers were included in this review. RESULTS: The results revealed that Mandarin-speaking children with CIs perform consistently more poorly in their production of consonants, in particular on fricatives, have a smaller and less well-defined vowel space, and exhibit greater difficulties in tone realisation, notably T2 and T3, when compared to their normal-hearing (NH) peers. The results from acoustic and accuracy analyses are negatively correlated with CI implantation age, but largely positively correlated with hearing age. CONCLUSIONS: Findings of this review highlight the factors that influence consonant, vowel and tone production in Mandarin-speaking children with CIs, thereby providing critical information for clinicians and researchers working with this population.

Audibility emphasis of low-level sounds improves consonant identification while preserving vowel identification for cochlear implant users.

Consonant perception is challenging for listeners with hearing loss, and transmission of speech over communication channels further deteriorates the acoustics of consonants. Part of the challenge arises from the short-term low energy spectro-temporal profile of consonants (for example, relative to vowels). We hypothesized that an audibility enhancement approach aimed at boosting the energy of low-level sounds would improve identification of consonants without diminishing vowel identification. We tested this hypothesis with 11 cochlear implant users, who completed an online listening experiment remotely using the media device and implant settings that they most commonly use when making video calls. Loudness growth and detection thresholds were measured for pure tone stimuli to characterize the relative loudness of test conditions. Consonant and vowel identification were measured in quiet and in speech-shaped noise for progressively difficult signal-to-noise ratios (+12, +6, 0, -6 dB SNR). These conditions were tested with and without an audibility-emphasis algorithm designed to enhance consonant identification at the source. The results show that the algorithm improves consonant identification in noise for cochlear implant users without diminishing vowel identification. We conclude that low-level emphasis of audio can improve speech recognition for cochlear implant users in the case of video calls or other telecommunications where the target speech can be preprocessed separately from environmental noise.

Consonant Age of Acquisition Reveals Nonlinear Effects in Nonword Repetition Performance.

Recent work has shown significant sublexical effects of long-term memory in nonword repetition (NWR) using a dichotomous consonant age of acquisition (CAoA) variable (Moore, 2018; Moore, Fiez, and Tompkins, 2017). Performance consistently decreased when stimuli comprised consonants acquired later versus earlier in speech development. To address potential confounds related to stimulus design and linearity, the purpose of this study was to test whether performance decreases as the CAoA value of stimuli increases in various linguistic tasks using a continuous CAoA variable. Thirty-one college students completed NWR and other linguistic tasks in which the stimuli varied in average CAoA values. Data were analyzed using multilevel modeling. After accounting for phonotactic probability, CAoA was a statistically significant predictor of performance across the models reported. The relationship was more complex in some of the models in which CAoA showed a statistically significant nonlinear relationship with the outcome measure. Results from this study support previous work showing that CAoA affects performance on NWR and other linguistic tasks that vary in their memory, auditory perceptual, and articulatory demands. Importantly, this line of work was extended here by demonstrating that the CAoA effect is robust across novel stimulus sets and study designs, and may be more complex than previously understood when using a dichotomous CAoA variable. Quadratic results suggest that the CAoA variable has a differential effect on performance for low to moderate CAoA values, but for higher CAoA values the effect is similarly negative. The nonlinear relationship between CAoA and measures of speed and accuracy on some of the tasks warrants further study into the complex relationship between various predictive factors that contribute to language performance.

Impact of auditory variables on consonant production in babbling and early speech in children with moderate hearing loss - a longitudinal study.

This longitudinal study aimed to investigate early consonant production and the impact of hearing aid (HA) use, and aided audibility in Swedish children with moderate hearing loss (CHL) who received amplification before 6 months of age. CHL (n = 11) and children with normal hearing (CNH) (n = 11) were followed-up at 10, 18, and 36 months of age. At 10 months of age, the CHL used significantly fewer oral stops (p < 0.01), dental/alveolar stops (p < 0.05) and had a significantly fewer number of different true consonants (p < 0.01). At 18 months, there were no significant differences between the groups regarding presence of oral stops, and dental/alveolar stops, but the significant difference in the number of different true consonants remained (p < 0.00). At 36 months of age, consonant proficiency did not differ between the groups. A higher number of hours of HA use was associated with the presence of consonant variables at 10 months. Aided audibility showed weak to moderate correlations with number of consonants produced and proficiency. This group of children presented with initial delays in their early consonant production but seemed to catch up as they aged. Consistency of HA use from initial fitting is an important factor that may decrease the possible delays in the development of early consonant production and proficiency in CHL by 36 months of age.