Search

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.

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.

Purpose: We evaluated whether naive listeners' ratings of the gender typicality of the speech of children assigned male at birth (AMAB) and children assigned female at birth (AFAB) were different at two time points: one at which children were 2.5-3.5 years old and one when they were 4.5-5.5 years old. We also examined whether measures of speech, language, and inhibitory control predicted developmental changes in these ratings. Method: A group of adults (N = 80) rated single-word productions of 55 AMAB and 55 AFAB children on a continuous scale from "definitely a boy" to "definitely a girl." Children's productions were taken from previous longitudinal study of phonological development and vocabulary growth. As part of that study, children completed a battery of standardized and nonstandardized tests at both time points. Results: Listener ratings for AMAB and AFAB children were significantly different at both time points. The difference was larger at the later time point, and this was due entirely to changes in the ratings of AMAB children's speech. A measure of language production and a measure of inhibitory control predicted developmental changes in these ratings, albeit only weakly, and not in a consistent direction. Conclusions: The gender typicality of AMAB and AFAB children's speech is perceptibly different for children as young as 2.5 years old. Developmental changes in perceived gender typicality are driven by changes in the speech of AMAB children. The learning of gendered speech is not constrained or facilitated by overall speech and language skill.

Purpose: We evaluated whether children whose inaccurate /[voiced alveolar approximant]/ productions showed evidence phonetic differentiation with /w/ at 3.5-4.5 years of age improved in /[voiced alveolar approximant]/ production over the next year more than children whose inaccurate productions did not show evidence of such differentiation. We also examined whether speech perception, inhibitory control, and vocabulary size predicted growth in /[voiced alveolar approximant]/. Method: A set of typically developing, monolingual English-speaking preschool children (n = 136) produced tokens of /[voiced alveolar approximant]/- and /w/-initial words at two time points (TPs), at which they were 39-52 and 51-65 months old. Children's productions of /[voiced alveolar approximant]/ and /w/ were narrowly phonetically transcribed. Children's productions at the earlier time point were rated by naïve listeners using a visual analog scale measure of phoneme goodness; these ratings were used to assess the degree of phonetic differentiation between /[voiced alveolar approximant]/ and /w/. Results: Accuracy for both phonemes varied considerably at both TPs. The growth in accuracy of /[voiced alveolar approximant]/ between the two TPs was not predicted by any individual-differences measures, nor by the degree of differentiation between /[voiced alveolar approximant]/ and /w/at the earlier time point. Conclusion: Low vocabulary size, low inhibitory control, poor speech perception, and the absence of early phonetic differentiation are not necessarily limiting factors in predicting /[voiced alveolar approximant]/ growth in individual children in the age range we studied.

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.

Purpose: Typically developing children assigned male at birth (AMAB) and children assigned female at birth (AFAB) produce the fricative /s/ differently: AFAB children produce /s/ with a higher spectral peak frequency. This study examined whether implicit knowledge of these differences affects speech‐language pathologists'/speech and language therapists' (SLPs'/SLTs') ratings of /s/ accuracy, by comparing ratings made in conditions where SLPs/SLTs were blind to children's sex assigned at birth (SAB) to conditions in which they were told this information. Methods: SLPs (n = 95) varying in clinical experience rated the accuracy of word‐initial /s/ productions (n = 87) of eight children with speech sound disorder in one of four conditions: one in which no information about the children was revealed, one in which children's SAB was revealed, one in which children's age was revealed, and one in which both were revealed. Results: Despite there being no statistically significant differences between AFAB and AMAB children's /s/ production in researcher‐determined accuracy or in one acoustic characteristic, spectral centroid, SLPs in all four conditions judged the /s/ productions of AFAB children as more accurate than AMAB children. Listeners were significantly less likely to judge the productions of AMAB children to be inaccurate in the conditions in which age or age and SAB were revealed. These effects were consistent across SLPs with greatly varying levels of clinical experience. Conclusion: Knowing or imputing children's age and SAB can affect ratings of /s/ accuracy. Clinicians should be mindful of these potential effects. Future research should understand how expectations about sociolinguistic variation in speech affect appraisals of their speech and language. WHAT THIS PAPER ADDS: What is already known on the subject: Adult men and women produce /s/ differently. A consensus is that these differences reflect sociolinguistic gender marking, rather than being the passive consequence of vocal‐tract differences. Recent studies have shown that children assigned female at birth (AFAB) and those assigned male at birth (AMAB) produce /s/ differently in ways that mirror the differences between adult men and women, and which presumably reflect gender marking. What this paper adds to existing knowledge: We asked whether US‐based speech‐language pathologists' (SLPs) ratings of the accuracy of /s/ differ depending on whether they are rating an AFAB or an AMAB child, and whether these differences are greater in conditions in which people are told the sex assigned at birth of the child being rated. We found that SLPs were more likely to judge AFAB children's /s/ productions to be more accurate than AMAB children's, even though the productions from the AMAB and AFAB children that were used as stimuli were matched for accuracy as determined by trained researchers. What are the clinical implications of this work?: SLPs/speech‐language therapists should be sensitive to the influence of social variables when assessing /s/. SLPs/speech‐language therapists might rate children's productions differently depending on whether they believe they are rating an AFAB or an AMAB child. [ABSTRACT FROM AUTHOR]

Much research in child speech development suggests that young children coarticulate more than adults. There are multiple, not mutually-exclusive, explanations for this pattern. For example, children may coarticulate more because they are limited by immature motor control. Or they may coarticulate more if they initially represent phonological segments in larger, more holistic units such as syllables or feet. We tested the importance of several different explanations for coarticulation in child speech by evaluating how four-year-olds' language experience, speech practice, and speech planning predicted their coarticulation between adjacent segments in real words and paired nonwords. Children with larger vocabularies coarticulated less, especially in real words, though there were no reliable coarticulatory differences between real words and nonwords after controlling for word duration. Children who vocalized more throughout a daylong audio recording also coarticulated less. Quantity of child vocalizations was more predictive of the degree of children's coarticulation than a measure of receptive language experience, adult word count. Overall, these results suggest strong roles for children's phonological representations and speech practice, as well as their immature fine motor control, for coarticulatory development.

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 /[voiceless dental fricative]/, /s/, /[esh - voiceless palato-alveolar fricative]/, /d/, /g/, /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.

Purpose: Some pronunciation patterns that are normal in 1 dialect might represent an error in another dialect (i.e., [ko(upsilon)l] for "cold," which is typical in African American English [AAE] but an error in many other dialects of English). This study examined whether trained speech-language pathologists and untrained listeners accommodate for presumed speaker dialect when rating children's productions of words. This study also explored whether effects of presumed race on perceived speech accuracy are mediated by individuals' knowledge and beliefs about AAE and their implicit attitudes about race. Method: Multiple groups of listeners rated the accuracy of a set of children's productions of words that have a distinct pronunciation in AAE. These were presented in 1 of 3 conditions: paired with no visual stimulus (to assess baseline accuracy) or paired with either African American children's faces (to suggest that the speaker uses AAE) or European American children's faces (to suggest that the speaker does not use AAE). Listeners also completed a set of measures of knowledge and attitudes about AAE and race, taken from previous studies. Results: Individuals in both groups rated children's productions more accurately when they were presented with African American children's faces than when paired with European American faces. The magnitude of this effect was generally similar across the 2 groups and was generally strongest for words that had been judged in the baseline condition to contain an error. None of the individual-differences measures predicted ratings. Conclusions: Assumptions about speaker attributes affect individuals' assessment of children's production accuracy. These effects are robust across trained and untrained listeners and cannot be predicted by existing measures of knowledge and attitudes about AAE and race.

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. [ABSTRACT FROM AUTHOR]

Purpose: Item response theory (IRT) is a psychometric approach to measurement that uses latent trait abilities (e.g., speech sound production skills) to model performance on individual items that vary by difficulty and discrimination. An IRT analysis was applied to preschoolers' productions of the words on the Goldman-Fristoe Test of Articulation-Second Edition (GFTA-2) to identify candidates for a screening measure of speech sound production skills. Method: The phoneme accuracies from 154 preschoolers, with speech skills on the GFTA-2 ranging from the 1st to above the 90th percentile, were analyzed with a 2- parameter logistic model. Results: A total of 108 of the 232 phonemes from stimuli in the sounds-in-words subtest fit the IRT model. These phonemes, and subgroups of the most difficult of these phonemes, correlated significantly with the children's overall percentile scores on the GFTA-2. Regression equations calculated for the 5 and 10 most difficult phonemes predicted overall percentile score at levels commensurate with other screening measures. Conclusions: These results suggest that speech production accuracy can be screened effectively with a small number of sounds. They motivate further research toward the development of a screening measure of children's speech sound production skills whose stimuli consist of a limited number of difficult phonemes.

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 and 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 and 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 and Implications: Results suggest that SSD is not associated with reduced phonological encoding ability, at least as it is reflected by cross-modal naming tasks.

Purpose The aims of the present study are (a) to quantify the developmental sequence of fricative mastery in Putonghua-speaking children and discuss the observed pattern in relation to existing theoretical positions, and (b) to describe the acquisition of the fine-articulatory/acoustic details of fricatives in the multidimensional acoustic space. Method Twenty adults and 97 children participated in a speech-production experiment, repeating a list of fricative-initial words. Two independent measures were applied to quantify the relative sequence of fricative acquisition: auditory-based phonetic transcription and acoustics-based statistical modeling. Two acoustic parameters--fricative centroid frequency and F2 onset--were used to index tongue-body and tongue-tip development, respectively. Results Both transcription and statistical modeling of acoustics yielded the sequence of /?/ ? /?/ ? /s/. Acoustic analysis further revealed gradual separation in both acoustic dimensions, with the initial undifferentiated form ambiguous between/?/ and /?/. Conclusions The observed sound-acquisition order was interpreted as reflecting a combined influence of both oromotor maturation and language-specific phoneme frequency in Putonghua. Acoustic results suggest a maturational advantage of the tongue body over the tongue tip during fricative development.

Purpose: The /r/ 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 /r/ 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 /r/. This study analyzed the effectiveness of automatically extracted F3-F2 differences in characterizing young children's productions of /r/--/w/ in comparison with manually coded measurements. Method: Automated F3-F2 differences were extracted from productions of a variety of different /r/- 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: [r], [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 (R² = .37) and narrow transcriptions (R² = .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 /r/--/w/ contrast. [ABSTRACT FROM AUTHOR]

Purpose: Debate around the underlying cognitive factors leading to poor performance in the repetition of nonwords by children with developmental impairments in language has centered around phonological short-term memory, lexical knowledge, and other factors. This study examines the impact of motor control demands on nonword repetition in groups of school children with specific impairments in language, working memory, or both. Method: Children repeated two lists of nonwords matched for motoric complexity either without constraint or with a gummi bear bite block held between their teeth. The bite block required motoric compensation to reorganize the motor plan for speech production. Results: Overall, the effect of the biomechanical constraint was very small for all groups. When analyses focused only on the most complex nonwords, children with language impairment were found to be significantly more impaired in the motorically constrained nonword repetition task than the typically developing group. In contrast, working memory difficulties were not differentially linked to motor condition. Conclusions: These findings add to the growing evidence that there is a motoric component to developmental language disorders. The results also suggest that the role of speech motor skill in nonword repetition is relatively modest.

Purpose: The authors examined the relationship between adults' perception of the accuracy of children's speech and acoustic detail in their subsequent productions to children. Method: Twenty-two adults participated in a task in which they rated the accuracy of 2- and 3-year-old children's word-initial /s/ and /[esh]/ using a visual analog scale (VAS), then produced a token of the same word as if they were responding to the child whose speech they had just rated. Result: The duration of adults' fricatives varied as a function of their perception of the accuracy of children's speech: Longer fricatives were produced following productions that they rated as inaccurate. This tendency to modify duration in response to perceived inaccurate tokens was mediated by measures of self-reported experience interacting with children. However, speakers did not increase the spectral distinctiveness of their fricatives following the perception of inaccurate tokens. Conclusion: These results suggest that adults modify temporal features of their speech in response to perceiving children's inaccurate productions. These longer fricatives are potentially both enhanced input to children and an error-corrective signal.

Purpose: This investigation examined the effect of repeated exposure to novel and repeated spoken words in typical environments on the intelligibility of 2 synthesized voices and human recorded speech in preschools. Method: Eighteen preschoolers listened to and repeated single words presented in human-recorded speech, DECtalk Paul, and AT&T Voice Michael during 5 experimental sessions. Stimuli consisted of repeated and novel words presented in each speech output condition during each session. Sessions took place in the presence of typically occurring noise in classroom or home settings. Results: There was a significant main effect for voice as participants accurately identified significantly more words in the human-recorded speech and AT&T Voice than in the DECtalk speech output condition. When averaged across speech output conditions, children increased their accuracy as they participated in additional sessions. There was a statistically significant interaction between session and voice. DECtalk had a slightly larger effect of session than did AT&T Voice and human-recorded speech. (Contains 4 tables and 2 figures.)

Purpose: This study examined whether experienced speech-language pathologists (SLPs) differ from inexperienced people in their perception of phonetic detail in children's speech. Method: Twenty-one experienced SLPs and 21 inexperienced listeners participated in a series of tasks in which they used a visual-analog scale (VAS) to rate children's natural productions of target /s/-/[theta]/, /t/-/k/, and /d/-/g/ in word-initial position. Listeners rated the perceived distance between individual productions and ideal productions. Results: The experienced listeners' ratings differed from the inexperienced listeners' ratings in four ways: They had higher intrarater reliability, showed less bias toward a more frequent sound, and were more closely related to the acoustic characteristics of the children's speech. In addition, the experienced listeners' responses were related to a different set of predictor variables. Conclusion: Results suggest that experience working as an SLP leads to better perception of phonetic detail in children's speech. Limitations and future research are discussed. (Contains 4 figures, 2 tables and 2 footnotes.)

We applaud Stoel-Gammon's (this issue) call for a more comprehensive account of the relationship between lexicon and phonology, and we strongly endorse her suggestions for future research. However, we think that it will not be enough simply to integrate findings and methods from the adult-centered and child-centered literatures. Both of these literatures suggest that we need to rethink standard assumptions about what phonological representations are and how they emerge to support the very large vocabularies that speakers develop over the course of a lifetime. Our commentary focuses on three themes relevant to this reconceptualization.

This article honours Adele Miccio's life work by reflecting on the utility of phonetic transcription. The first section reviews the literature on cases where children whose speech appears to neutralize a contrast in the adult language are found on closer examination to produce a contrast ("covert contrast"). This study presents evidence from a new series of perception studies that covert contrast may be far more prevalent in children's speech than existing studies would suggest. The second section presents the results of a new study designed to examine whether naive listeners' perception of children's /s/ and /[theta]/ productions can be changed experimentally when they are led to believe that the children who produced the sounds were older or younger. Here, it is shown that, under the right circumstances, adults report more tokens of /[theta]/ to be accurate productions of /s/ when they believe a talker to be an older child than when they believe the talker to be younger. This finding suggests that auditory information alone cannot be the sole basis for judging the accuracy of a sound. The final section presents recommendations for supplementing phonetic transcription with other measures, to gain a fuller picture of children's production abilities. (Contains 2 tables and 3 figures.)

This brief communication is a response to the article "The prevalence of lisping in gay men" (Van Borsel, J., De Bruyn, E., Lefebvre, E., Sokoloff, A., De Ley, S., & Baudonck, N. 2009. "Journal of Communication Disorders, 42", 100-106). I argue aspects of that study's design, measurement, and interpretation limit the strength of its authors' conclusions that there is a higher incidence of lisping in gay men than in heterosexual men. Suggestions for further research are presented.

Previous studies have shown that a subset of gay, lesbian, and bisexual (GLB) and heterosexual adults produce distinctive patterns of phonetic variation that allow listeners to detect their sexual orientation from audio-only samples of read speech. The current investigation examined the extent to which judgments of sexual orientation from speech are related to judgments of masculinity or femininity made by an independent group of listeners. It also examined the acoustic measures that predict perceived sexual orientation and perceived masculinity/femininity. Ten listeners judged the perceived masculinity or femininity of 44 talkers (11 heterosexual men, 11 heterosexual women, 11 gay men, and 11 lesbian or bisexual women). These were compared to measures of the talkers' perceived sexual orientation, and to acoustic measures of the talker's speech. Listeners judged gay men to sound less masculine than heterosexual men, and lesbian/bisexual women to sound less feminine than heterosexual women. These measures were significantly correlated with measures of perceived sexual orientation. Regression analyses showed that different sets of acoustic measures predicated perceived sexual orientation and perceived masculinity/femininity, and that some acoustic measures were more strongly correlated with one perceptual measure than the other. Results suggest that perceived sexual orientation, perceived masculinity, and perceived femininity are distinct but correlated perceptual parameters. (Contains 1 table, 2 figures, and 2 footnotes.)

Susan Gathercole's Keynote Article (2006) is an impressive summary of the literature on nonword repetition and its relationship to word learning and vocabulary size. When considering research by Mary Beckman, Jan Edwards, and myself, Gathercole speculates that our finding of a stronger relationship between vocabulary measures and repetition accuracy for low-frequency sequences than for high-frequency sequences is due to differences in the range of the two measures. In our work on diphone repetition (e.g., Edwards, Beckman, & Munson, 2004; Munson, Edwards, & Beckman, 2005) we tried to increase the range in our dependent measures by coding errors on a finer grained scale than simple correct/incorrect scoring would allow. Moreover, restriction of range does not appear to be the driving factor in the relationship between vocabulary size and the difference between high- and low-frequency sequence repetition accuracy (what we call the "frequency effect") in at least one of our studies (Munson et al., 2005). When the children with the 50 lowest mean accuracy scores for high-frequency sequences were examined, vocabulary size accounted for 10.5% of the variance in the frequency effect beyond what was accounted for by chronological age. When the 50 children with the highest mean accuracy scores for high-frequency sequences were examined (a group in which the range of high-frequency accuracy scores was more compressed, arguably reflecting ceiling effects), an estimate of vocabulary size accounted for only 6.9% of the frequency effect beyond chronological age. The associated beta coefficient was significant only at the alpha less than 0.08 level. This is the opposite pattern than Gathercole's argument would predict.

Research has shown that children repeat high-probability phoneme sequences more accurately than low-probability ones. This effect attenuates with age, and its decrease is predicted by developmental changes in the size of the lexicon (J. Edwards, M. E. Beckman, & B. Munson, 2004; B. Munson, 2001; B. Munson, J. Edwards, & M. Beckman, 2005). This study expands on these findings by examining relationships between vocabulary size and repetition accuracy of nonwords varying in phonotactic probability by 16 children with specific language impairment (SLI), 16 chronological-age-matched (CA) peers with typical speech and language development, and 16 younger children matched with the children with SLI on vocabulary size (VS). As in previous research, children with SLI repeated nonwords less accurately than did CA children. The children with SLI and the VS children showed similar levels of nonword repetition accuracy. Phonotactic probability affected repetition accuracy more for children with SLI and VS children than for CA children. Regression analyses showed that measures of vocabulary size were the best predictor of the difference in repetition accuracy between high- and low-probability sequences. Analyses by items showed that measures of phonotactic probability were stronger predictors of repetition accuracy than judgments of wordlikeness. Taken together, the results support research demonstrating that vocabulary size mediates the influence of phonotactic probability on nonword repetition, perhaps due to its influence on the ongoing refinement of phonological categories. (Contains 3 figures, 1 footnote, and 5 tables.)

This study examined the structure of children's mental lexicons through performance on 2 short experimental tasks, 1 in which children repeated familiar monosyllabic real words varying in neighborhood density and 1 in which they repeated CVC nonwords varying in phonotactic probability. Two groups of typically developing children with mean ages of 4;3 (years; months; n = 16) and 7;2 (n = 15) participated. In the group of younger children, offset-to-onset response latencies were not systematically affected by lexicality, phonotactic probability, or neighborhood density. Onset-to-onset latencies showed an effect of phonotactic probability on nonword repetition. Children in the older group repeated high-density real words with longer latencies than low-density real words. They also repeated high-probability nonwords with shorter latencies than low-probability nonwords. This was true for both the onset-to-onset andoffset-to-onset repetition latencies. Children in both age groups repeated vowels embedded in high-probability nonwords with shorter durations than vowels embedded in low-probability nonwords. These findings suggest that lexical competition and phonological facilitation emerge in development and that the rate of development is different for different dependent measures.KEY WORDS: phonological neighborhood density, phonotactic probability, nonword repetition, real-word repetition, children

A growing body of research has documented effects of phonotactic probability on young children's nonword repetition. This study extends this research in 2 ways. First, it compares nonword repetitions by 40 young children with phonological disorders with those by 40 same-age peers with typical phonological development on a nonword repetition task in which the frequency of embedded diphone sequences was varied. Second, it examines the relationship between the frequency effect in the nonword repetition task and other measures of linguistic ability in these children. Children in both groups repeated low-frequency sequences less accurately than high-frequency sequences. The children with phonological disorders were less accurate overall but showed no larger disadvantage for the low-frequency sequences than their age peers. Across the group, the size of the frequency effect was correlated with vocabulary size, but it was independent of measures of speech perception and articulatory ability. These results support the hypothesis that the production difficulty associated with low-frequency sequences is related primarily to vocabulary growth rather than to developments in articulatory or perceptual ability. By contrast, production problems experienced by children with phonological disorders do not appear to result from difficulties in making abstractions over known lexical items. Instead, they may be associated with difficulties in building representations in the primary sensory and motor domains.KEY WORDS: nonword repetition, phonological disorder, vocabulary size, speech perception, frequency

This article discusses 4 types of phonological knowledge: knowledge of the acoustic and perceptual characteristics of speech sounds (perceptual knowledge), knowledge of the articulatory characteristics of speech sounds (articulatory knowledge), higher level knowledge of the ways that words can be divided into sounds and related phonotactic constraints on how sounds can be combined into words (higher level phonological knowledge), and knowledge of the ways that variation in pronunciation can be used to convey social identity (social-indexical knowledge). The first section of the article discusses the nature of these types of knowledge in adults. The second describes how they develop in children with typical language development. The third section outlines how different types of knowledge may be compromised in children with functional speech-sound impairments. Together these 5 sections serve as a review for practicing clinicians of the types of phonological knowledge that underlie accurate and fluent speech production.

Two experiments examined whether listening to multiple presentations of recorded speech stimuli influences the reliability and accuracy of judgments of children's speech production accuracy. In Experiment 1, 10 listeners phonetically transcribed words produced by children with phonological impairments after a single presentation and after the word was played 7 times. Inter- and intratranscriber reliability in the single- and multiple-presentation conditions did not differ significantly. In Experiment 2, 18 listeners provided binary correct/incorrect judgments of /s/ accuracy in single- and multiple-presentation conditions. There was no systematic effect of presentation condition on either accuracy or intrarater reliability. However, greater interrater reliability was noted in the multiple-presentation condition, particularly for tokens of /s/ that were incorrect or acoustically intermediate between an incorrect and a correct /s/. Taken together, the results suggest that multiple presentations have no measurable effect on the accuracy and intrarater reliability of judgments of children's phonetic accuracy, but that they do have a small effect on interrater reliability. Clinical implications are discussed.

Recent literature suggests that phonological neighborhood density and word frequency can affect speech production, in addition to the well-documented effects that they have on speech perception. This article describes 2 experiments that examined how phonological neighborhood density influences the durations and formant frequencies of adults' productions of vowels in real words. In Experiment 1, 10 normal speakers produced words that covaried in phonological neighborhood density and word frequency. Infrequent words with many phonological neighbors were produced with shorter durations and more expanded vowel spaces than frequent words with few phonological neighbors. Results of this experiment confirmed that this effect was not related to the duration of the vowels constituting the high- and low-density words. In Experiment 2, 15 adults produced words that varied in both word frequency and neighborhood density. Neighborhood density affected vowel articulation in both high- and low-frequency words. Moreover, frequent words were produced with more contracted vowel spaces than infrequent words. There was no interaction between these factors, and the vowel duration did not vary as a function of neighborhood density. Taken together, the results suggest that neighborhood density affects vowel production independent of word frequency and vowel duration.KEY WORDS: phonological neighborhood density, word frequency, vowels, acoustic measurements, adults