The everyday speech environments of preschoolers with and without cochlear implants.

Children who receive cochlear implants develop spoken language on a protracted timescale. The home environment facilitates speech-language development, yet it is relatively unknown how the environment differs between children with cochlear implants and typical hearing. We matched eighteen preschoolers with implants (31-65 months) to two groups of children with typical hearing: by chronological age and hearing age. Each child completed a long-form, naturalistic audio recording of their home environment (appx. 16 hours/child; >730 hours of observation) to measure adult speech input, child vocal productivity, and caregiver-child interaction. Results showed that children with cochlear implants and typical hearing were exposed to and engaged in similar amounts of spoken language with caregivers. However, the home environment did not reflect developmental stages as closely for children with implants, or predict their speech outcomes as strongly. Home-based speech-language interventions should focus on the unique input-outcome relationships for this group of children with hearing loss.

Preschoolers rely on rich speech representations to process variable speech.

To learn language, children must map variable input to categories such as phones and words. How do children process variation and distinguish between variable pronunciations ("shoup" for soup) versus new words? The unique sensory experience of children with cochlear implants, who learn speech through their device's degraded signal, lends new insight into this question. In a mispronunciation sensitivity eyetracking task, children with implants (N = 33), and typical hearing (N = 24; 36-66 months; 36F, 19M; all non-Hispanic white), with larger vocabularies processed known words faster. But children with implants were less sensitive to mispronunciations than typical hearing controls. Thus, children of all hearing experiences use lexical knowledge to process familiar words but require detailed speech representations to process variable speech in real time.

Effects of Device Limitations on Acquisition of the /t/-/k/ Contrast in Children With Cochlear Implants.

OBJECTIVES: The present study investigated how development of the /t/-/k/ contrast is affected by the unique perceptual constraints imposed on young children using cochlear implants (CIs). We hypothesized that children with CIs would demonstrate unique patterns of speech acquisition due to device limitations, rather than straightforward delays due to a lack of auditory input in the first year of life before implantation. This study focused on the contrast between /t/ and /k/ because it is acquired early in the sequence of development, requires less advanced motor control than later-acquired place contrasts, is differentiated by spectral cues (which are particularly degraded when processed by CIs), and is not easily differentiated by visual cues alone. Furthermore, perceptual confusability between /t/ and /k/ may be exacerbated in front-vowel contexts, where the spectral energy for /k/ is shifted to higher frequencies, creating more spectral overlap with /t/. DESIGN: Children with CIs (n = 26; ages 31 to 66 mo) who received implants around their first birthdays were matched to peers with normal hearing (NH). Children participated in a picture-prompted auditory word-repetition task that included over 30 tokens of word-initial /t/ and /k/ consonants. Tokens were balanced across front-vowel and back-vowel contexts to assess the effects of coarticulation. Productions were transcribed and coded for accuracy as well as the types of errors produced (manner of articulation, voicing, or place of articulation errors). Centroid frequency was also calculated for /t/ and /k/ tokens that were produced correctly. Mixed-effects models were used to compare accuracy, types of errors, and centroid frequencies across groups, target consonants, and vowel contexts. RESULTS: Children with CIs produced /t/ and /k/ less accurately than their peers in both front- and back-vowel contexts. Children with CIs produced /t/ and /k/ with equal accuracy, and /k/ was produced less accurately in front-vowel contexts than in back-vowel contexts. When they produced errors, children with CIs were more likely to produce manner errors and less likely to produce voicing errors than children with NH. Centroid frequencies for /t/ and /k/ were similar across groups, except for /k/ in front-vowel contexts: children with NH produced /k/ in front-vowel contexts with higher centroid frequency than children with CIs, and they produced /k/ and /t/ with equal centroid frequencies in front-vowel contexts. CONCLUSIONS: Children with CIs not only produced /t/ and /k/ less accurately than peers with NH, they also demonstrated idiosyncratic patterns of acquisition, likely resulting from receiving degraded and distorted spectral information critical for differentiating /t/ and /k/. Speech-language pathologists should consider perceptual confusability of consonants (and their allophonic variations) during their assessment and treatment of this unique population of children.

Fundamental frequency range and other acoustic factors that might contribute to the clear-speech benefit.

The main goal of the present study was to assess the role of the fundamental frequency (F0) range on the clear-speech benefit. Conversational- and clear-speech sentences were recorded for four male speakers: the speakers' clear-speech productions had slower speaking rates, wider F0 range, more high-frequency energy, expanded vowel space, and higher vocal intensity level relative to their conversational-speech productions. To examine if F0 range contributes to the clear-speech benefit, the F0 range of clear-speech sentences was compressed to match that of the speakers' conversational-speech sentences. Fifteen listeners were presented with conversational, clear, and F0-compressed sentences in sustained speech-shaped noise. All talkers elicited substantial intelligibility benefits (keyword percent correct) from clear and F0-compressed speech when compared with conversational speech. There was no significant difference in performance between clear and F0-compressed speech. These results leave open the possibility that a clear-speech benefit could be a result of its F0 contours rather than its wide F0 range. Intelligibility predictions based on acoustic characteristics of clear speech, specifically high-frequency emphasis and pauses, accounted for either small or negligible amounts of the clear-speech benefit.

The influence of lexical characteristics and talker accent on the recognition of English words by native speakers of Korean.

This study investigated the influences of lexical characteristics and talker accent on English spoken word recognition by first-language (L1) Korean second-language (L2) speakers of English. Stimuli were words that varied in phonological neighborhood density (PND) and word frequency (WF), produced by a L1 English speaker (L1 talker) and a L1 Korean speaker (L2 talker). Participants were 60 listeners from three groups: 20 L1 English speakers, 20 Korean L2 English speakers studying in the United States, and 20 Korean L2 English speakers studying in Korea. The 40 L2 English speakers varied widely in their estimated English proficiency. The results showed significant main effects of talkers, PND, and listener proficiency on word-recognition accuracy as well as significant interactions among stimulus talker (i.e., L1 vs L2 talker), PND, and WF and between stimulus talker and listener groups. However, we did not find that PND differentially affects word recognition in L2 learners, as had been found previously by Imai et al. [(2005). J. Acoust. Soc. Am. 117, 896-907] using the same design. Instead, our results paralleled closely those of Yoneyama and Munson [(2017). J. Acoust. Soc. Am. 141, 1308-1320], who examined L2 English speakers whose L1 was Japanese. These findings are discussed in light of the influence of L1 lexical structure on L2 phonological processing.

Auditory feedback experience in the development of phonetic production: Evidence from preschoolers with cochlear implants and their normal-hearing peers.

Previous work has found that preschoolers with greater phonological awareness and larger lexicons, who speak more throughout the day, exhibit less intra-syllabic coarticulation in controlled speech production tasks. These findings suggest that both linguistic experience and speech-motor control are important predictors of spoken phonetic development. Still, it remains unclear how preschoolers' speech practice when they talk drives the development of coarticulation because children who talk more are likely to have both increased fine motor control and increased auditory feedback experience. Here, the potential effect of auditory feedback is studied by examining a population-children with cochlear implants (CIs)-which is naturally differing in auditory experience. The results show that (1) developmentally appropriate coarticulation improves with an increased hearing age but not chronological age; (2) children with CIs pattern coarticulatorily closer to their younger, hearing age-matched peers than chronological age-matched peers; and (3) the effects of speech practice on coarticulation, measured using naturalistic, at-home recordings of the children's speech production, only appear in the children with CIs after several years of hearing experience. Together, these results indicate a strong role of auditory feedback experience on coarticulation and suggest that parent-child communicative exchanges could stimulate children's own vocal output, which drives speech development.

Clinical experience and categorical perception of children's speech.

BACKGROUND: Accurate and detailed records of children's speech are a critical component of competent service delivery in speech-language pathology/speech and language therapy (SLP/SLT). Previous research has shown that during speech-sound acquisition, children gradually learn to produce sounds in adult-like manners. Continuous rating scales are a way to track this gradual learning. AIMS: To examine whether clinical experience affects the ability and willingness to rate children's speech production using continuous rating scales. METHODS & PROCEDURES: An online survey was administered to 81 US-based SLPs/SLTs, binned into more- and less-experienced groups, and 20 non-SLPs/SLTs. The survey included a speech-sound rating task in which participants rated the production of place of articulation in children's productions of word-initial /θ/, /s/, /ʃ/, /d/, /ɡ/, /t/ and /k/ on a nine-point equally appearing interval scale. We examined the extent to which these were accurate (i.e., the extent to which they matched laboratory measures of production characteristics) and the extent to which the ratings were gradual (i.e., they used the entire rating scales, rather than just the endpoints). MAIN CONTRIBUTION: There were no consistent differences between non-SLPs/SLTs, less-experienced SLPs/SLTs and more-experienced SLPs/SLTs in a measure of the accuracy of responses. More consistent differences were found in the extent to which listeners used the endpoints of the scale: greater experience was associated with greater use of the endpoint values. CONCLUSIONS & IMPLICATIONS: More-experienced SLPs/SLTs are less likely to use the entire range of continuous rating scales to rate children's speech accuracy than less-experienced SLPs/SLTs or clinically untrained listeners. Implications for service delivery are discussed. What this paper adds What is already known on the subject Children's productions of individual sounds, like /k/, become gradually more adult-like over the course of development. For a child who has a [t] for /k/ error, this gradual development means that children's productions become progressively less like /t/ and more like /k/ over development. Phonetic transcription does not capture this gradual development. In contrast, studies have shown that continuous ratings of children's speech (such as rating productions on a scale anchored by the text "the 't' sound" at one end and "the 'k' sound" at the other end) can capture this gradual development. What this paper adds to existing knowledge To determine continuous ratings are clinically feasible, we must first determine whether clinical experience affects people's use of continuous rating scales to rate children's speech. We conducted an on-line speech perception experiment in which 81 speech-language pathologists/speech and language therapists (SLPs/SLTs) and 20 non-SLPs/SLTs rated 60 productions by children on continuous rating scales. The 60 stimuli included many sounds that had been independently verified to be intermediate productions (i.e., a target /k/ that was neither completely /k/-like nor completely /t/-like). Non-SLPs/SLTs and less-experienced SLPs/SLTs rated those intermediate sounds with intermediate ratings (i.e., somewhere on the midpoint of a continuous scale). In contrast, more-experienced SLPs/SLTs were more likely to rate those sounds as instances of endpoints (i.e., as either /k/ or /t/). What are the potential or actual clinical implications of this work? This finding suggests that clinical experience is paradoxically associated with a reduced tendency to use the entire range of responses on continuous rating scales. This finding suggests that we must better understand the cause of this reduced tendency, so that clinicians at all levels can use continuous rating scales equally effectively.

A lexical advantage in four-year-old children's word repetition.

This study examined a potential lexicality advantage in young children's early speech production: do children produce sound sequences less accurately in nonwords than real words? Children aged 3;3-4;4 completed two tasks: a real word repetition task and a corresponding nonword repetition task. Each of the 23 real words had a paired consonant-vowel sequence in the nonword in word-initial position (e.g., 'su' in ['sutkes] 'suitcase' and ['sudrɑs]). The word-initial consonant-vowel sequences were kept constant between the paired words. Previous work on this topic compared different sequences of paired sounds, making it hard to determine if those results were due to a lexical or phonetic effect. Our results show that children reliably produced consonant-vowel sequences in real words more accurately than nonwords. The effect was most pronounced in children with smaller receptive vocabularies. Together, these results reinforce theories arguing for interactions between vocabulary size and phonology in language development.

Spectral and temporal measures of coarticulation in child speech.

Speech produced by children is characterized by a high fundamental frequency which complicates measurement of vocal tract resonances, and hence coarticulation. Here two whole-spectrum measures of coarticulation are validated, one temporal and one spectral, that are less sensitive to these challenges. Using these measures, consonant-vowel coarticulation is calculated in the speech of a large sample of 4-year-old children. The measurements replicate known lingual coarticulatory findings from the literature, demonstrating the utility of these acoustic measures of coarticulation in speakers of all ages.

Public perceptions of traumatic brain injury: predictors of knowledge and the effects of education.

AIM: Existing research suggests that the public demonstrates inadequate knowledge about traumatic brain injury (TBI), indicating a need for public education initiatives; however, limited research exists on the effectiveness of these initiatives. The purposes of this study were to (1) identify whether any demographic/personal variables (e.g. gender, age, experience with TBI) predicted TBI knowledge and (2) determine whether presenting an educational video to members of the general public would improve knowledge about TBI. METHODS: Participants included 392 adults recruited from a state fair. Participants were divided into two groups, one of which viewed a 6-min video about TBI, and one which viewed an unrelated video. Participants completed measures relating to their backgrounds and knowledge about TBI. RESULTS: Greater educational attainment and professional experience with TBI were predictive of better TBI knowledge (F(1, 336) = 13.76 and 6.92, respectively, p < 0.01); no other demographic or personal variables predicted knowledge. Participants who viewed the TBI video demonstrated significantly better knowledge than participants who did not (F(1, 336) = 52.41, p < 0.0001). CONCLUSION: These results indicate that public education can result in immediate gains in public knowledge about TBI. Further research should include randomized controlled trials to determine long-term effectiveness of public education campaigns.

The influence of lexical characteristics and talker accent on the recognition of English words by speakers of Japanese.

Whether or not the influence of listeners' language proficiency on L2 speech recognition was affected by the structure of the lexicon was examined. This specific experiment examined the effect of word frequency (WF) and phonological neighborhood density (PND) on word recognition in native speakers of English and second-language (L2) speakers of English whose first language was Japanese. The stimuli included English words produced by a native speaker of English and English words produced by a native speaker of Japanese (i.e., with Japanese-accented English). The experiment was inspired by the finding of Imai, Flege, and Walley [(2005). J. Acoust. Soc. Am. 117, 896-907] that the influence of talker accent on speech intelligibility for L2 learners of English whose L1 is Spanish varies as a function of words' PND. In the currently study, significant interactions between stimulus accentedness and listener group on the accuracy and speed of spoken word recognition were found, as were significant effects of PND and WF on word-recognition accuracy. However, no significant three-way interaction among stimulus talker, listener group, and PND on either measure was found. Results are discussed in light of recent findings on cross-linguistic differences in the nature of the effects of PND on L2 phonological and lexical processing.

Phonological encoding in speech-sound disorder: evidence from a cross-modal priming experiment.

BACKGROUND: Psycholinguistic models of language production provide a framework for determining the locus of language breakdown that leads to speech-sound disorder (SSD) in children. AIMS: To examine whether children with SSD differ from their age-matched peers with typical speech and language development (TD) in the ability phonologically to encode lexical items that have been accessed from memory. METHODS & PROCEDURES: Thirty-six children (18 with TD, 18 with SSD) viewed pictures while listening to interfering words (IW) or a non-linguistic auditory stimulus presented over headphones either 150 ms before, concurrent with or 150 ms after picture presentation. The phonological similarity of the IW and the pictures' names varied. Picture-naming latency, accuracy and duration were tallied. OUTCOMES & RESULTS: All children named pictures more quickly in the presence of an IW identical to the picture's name than in the other conditions. At the +150 ms stimulus onset asynchrony, pictures were named more quickly when the IW shared phonemes with the picture's name than when they were phonologically unrelated to the picture's name. The size of this effect was similar for children with SSD and children with TD. Variation in the magnitude of inhibition and facilitation on cross-modal priming tasks across children was more strongly affected by the size of the expressive and receptive lexicons than by speech-production accuracy. CONCLUSIONS & IMPLICATIONS: Results suggest that SSD is not associated with reduced phonological encoding ability, at least as it is reflected by cross-modal naming tasks.

Gradient perception of children's productions of /s/ and /θ/: A comparative study of rating methods.

Past studies have shown incontrovertible evidence for the existence of covert contrasts in children's speech, i.e. differences between target productions that are nonetheless transcribed with the same phonetic symbol. Moreover, there is evidence that these are relevant to forming prognoses and tracking progress in children with speech sound disorder. A challenge remains to determine the most efficient and reliable methods for assessing covert contrasts. This study investigates how readily listeners can identify covert contrasts in children's speech when using a continuous rating scale in the form of a visual analogue scale (VAS) to denote children's productions. Individual listeners' VAS responses were found to correlate statistically significantly with a variety of continuous measures of children's production accuracy, including judgements of binary accuracy pooled over a large set of listeners. These findings reinforce the growing body of evidence that VAS judgements are potentially useful clinical measures of covert contrast.

Bias in the perception of phonetic detail in children's speech: A comparison of categorical and continuous rating scales.

Previous research has shown that continuous rating scales can be used to assess phonetic detail in children's productions, and could potentially be used to detect covert contrasts. Two experiments examined whether continuous rating scales have the additional benefit of being less susceptible to task-related biasing than categorical phonetic transcriptions. In both experiments, judgements of children's productions of /s/ and /θ/ were interleaved with two types of rating tasks designed to induce bias: continuous judgements of a parameter whose variation is itself relatively more continuous (gender typicality of their speech) in one biasing condition, and categorical judgements of a parameter that is relatively less continuous (the vowel they produced) in the other biasing condition. One experiment elicited continuous judgements of /s/ and /θ/ productions, while the other elicited categorical judgements. The results of Experiment 1 showed that the influence of acoustic characteristics on continuous judgements of /s/ and /θ/ was stable across biasing conditions. In contrast, the results of Experiment 2 showed that the influence of acoustic characteristics on categorical judgements of /s/ and /θ/differed systematically across biasing conditions. These results suggest that continuous judgements are psychometrically superior to categorical judgements, as they are more resistant to task-related bias.

THE INFLUENCE OF LEXICAL FACTORS ON VOWEL DISTINCTIVENESS: EFFECTS OF JAW POSITIONING.

The phonetic characteristics of words are influenced by lexical characteristics, including word frequency and phonological neighborhood density (Baese-Berke & Goldrick, 2009; Wright, 2004). In our previous research, we replicated this effect with neurologically healthy young adults (Munson & Solomon, 2004). In research with the same set of participants, we showed that speech sounded less natural when produced with bite blocks than with an unconstrained jaw (Solomon, Makashay, & Munson, 2016). The current study combined these concepts to examine whether a bite-block perturbation exaggerated or reduced the effects of lexical factors on normal speech. Ten young adults produced more challenging lexical stimuli (i.e. infrequent words with many phonological neighbors) with shorter vowels and more disperse F1/F2 spaces than less challenging words (i.e. frequent words with few phonological neighbors). This difference was exaggerated when speaking with a 10-mm bite block, though the interaction between jaw positioning and lexical competition did not achieve statistical significance. Results indicate that talkers alter vowel characteristics in response both to biomechanical and linguistic demands, and that the effect of lexical characteristics is robust to the articulatory reorganization required for successful bite-block compensation.

The Effect of Jaw Position on Perceptual and Acoustic Characteristics of Speech.

Bite blocks are used to stabilize the jaw and to isolate tongue and lip movements from that of the mandible during speech and nonspeech activities. Ten normally speaking young adults produced sentences with an unconstrained jaw and with unilateral placement of 2-mm and 5-mm bite blocks. Six listeners rated sentences spoken without either bite block as the most natural sounding. Spectral characteristics of /s/, /ʃ/ and /t/ (sibilant frication and stop bursts) differed significantly with than without bite blocks, such that mean spectral energy decreased, and variation and skew of spectral energy increased. Spectral kurtosis did not change for the group, but 2 participants exhibited highly kurtotic /s/ spectra without a bite block that normalized with bite blocks. The second formant frequency for the high vowel /i/ was lower with bite blocks; there was no systematic difference in F2 slope for diphthongs. Segmental and suprasegmental timing of speech articulation was not affected significantly by these small bite blocks. This study provides support for using small bite blocks to isolate the tongue from the jaw without large effects on speech, but cautions that speech is likely to sound less natural than when produced with an unconstrained jaw.

Gender typicality in children's speech: A comparison of boys with and without gender identity disorder.

This study examined whether boys with gender identity disorder (GID) produced less prototypically male speech than control boys without GID, a possibility that has been suggested by clinical observations. Two groups of listeners participated in tasks where they rated the gender typicality of single words (group 1) or sentences (group 2) produced by 15 5-13 year old boys with GID and 15 age-matched boys without GID. Detailed acoustic analyses of the stimuli were also conducted. Boys with GID were rated as less boy-like than boys without GID. In the experiment using sentence stimuli, these group differences were larger than in the experiment using single-word stimuli. Listeners' ratings were predicted by a variety of acoustic parameters, including ones that differ between the two groups and ones that are stereotypically associated with adult men's and women's speech. Future research should examine how these variants are acquired.

Clinical Focus: The Development and Description of a Palette of Transmasculine Voices.

PURPOSE: The study of gender and speech has historically excluded studies of transmasculine individuals. Consequently, generalizations about speech and gender are based on cisgender individuals. This lack of representation hinders clinical training and clinical service delivery, particularly by speech-language pathologists providing gender-affirming communication services. This letter describes a new corpus of the speech of American English-speaking transmasculine men, transmasculine nonbinary people, and cisgender men that is open and available to clinicians and researchers. METHOD: Twenty masculine-presenting native English speakers from the Upper Midwestern United States (including cisgender men, transmasculine men, and transmasculine nonbinary people) were recorded, producing three sets of speech materials: Consensus Auditory-Perceptual Evaluation of Voice sentences, the Rainbow Passage, and a novel set of sentences developed for this project. Acoustic measures vowels (overall formant frequency scaling, vowel-space dispersion, fundamental frequency, breathiness), consonants (voice onset time of word-initial voiceless stops, spectral moments of word-initial /s/), and the entire sentence (rate of speech) that were made. RESULTS: The acoustic measures reveal a wide range for all dependent measures and low correlations among the measures. Results show that many of the voices depart considerably from the norms for men's speech in published studies. CONCLUSION: This new corpus can be used to illustrate different ways of sounding masculine by speech-language pathologists performing gender-affirming communication services and by higher education teachers as examples of diverse ways of sounding masculine.

Relating Acoustic Measures to Listener Ratings of Children's Productions of Word-Initial /ɹ/ and /w/.

PURPOSE: The /ɹ/ productions of young children acquiring American English are highly variable and often inaccurate, with [w] as the most common substitution error. One acoustic indicator of the goodness of children's /ɹ/ productions is the difference between the frequency of the second formant (F2) and the third formant (F3), with a smaller F3-F2 difference being associated with a perceptually more adultlike /ɹ/. This study analyzed the effectiveness of automatically extracted F3-F2 differences in characterizing young children's productions of /ɹ/-/w/ in comparison with manually coded measurements. METHOD: Automated F3-F2 differences were extracted from productions of a variety of different /ɹ/- and /w/-initial words spoken by 3- to 4-year-old monolingual preschoolers (N = 117; 2,278 tokens in total). These automated measures were compared to ratings of the phoneme goodness of children's productions as rated by untrained adult listeners (n = 132) on a visual analog scale, as well as to narrow transcriptions of the production into four categories: [ɹ], [w], and two intermediate categories. RESULTS: Data visualizations show a weak relationship between automated F3-F2 differences with listener ratings and narrow transcriptions. Mixed-effects models suggest the automated F3-F2 difference only modestly predicts listener ratings (R 2 = .37) and narrow transcriptions (R 2 = .32). CONCLUSION: The weak relationship between automated F3-F2 difference and both listener ratings and narrow transcriptions suggests that these automated acoustic measures are of questionable reliability and utility in assessing preschool children's mastery of the /ɹ/-/w/ contrast.

Verbs Matter: A Tutorial for Determining Verb Difficulty.

PURPOSE: Research indicates that when teaching grammatical forms to children, the verbs used to model specific grammatical inflections matter. When learning grammatical forms, children have higher performance when they hear many unique verb forms that vary in their frequency and phonological complexity. In this tutorial, we demonstrate a method for identifying and characterizing a large number of verbs based on their frequency and complexity. METHOD: We selected verbs from an open-access database of transcribed child language samples. We extracted verbs produced by 5- to 8.9-year-old children in four morphosyntactic contexts: regular past tense -ed, third person singular -s, is/are + verb+ing, and do/does questions. We ranked verbs based on their frequency of occurrence across transcripts. We also coded the phonological complexity of each verb. We coded each verb as high or low frequency and high or low phonological complexity. RESULTS: The synthesis yielded 129 unique verbs used in the regular past tense -ed context, 107 verbs used in the third person singular -s context, 69 verbs used in the is/are + verb+ing context, and 16 verbs used in the do/does question context. We created tables for each form that include the frequency rankings and phonological complexity scores for every verb. CONCLUSIONS: Clinicians may use the verb lists, frequency ratings, and phonological complexity scores to help identify verbs to incorporate into assessment and intervention sessions with children. Researchers and clinicians may use the step-by-step approach presented in the tutorial to identify verbs or other syntactic components used in different morphosyntactic contexts or produced by individuals of different demographics in different speaking contexts.