Intraword variability in typical speech development

Accuracy of Speech Sound Analysis: Comparison of an Automatic Artificial Intelligence Algorithm With Clinician Assessment

PURPOSE

Automatic speech analysis (ASA) and automatic speech recognition systems are increasingly being used in the treatment of speech sound disorders (SSDs). When utilized as a home practice tool or in the absence of the clinician, the ASA system has the potential to facilitate treatment gains. However, the feedback accuracy of such systems varies, a factor that may impact these gains. The current research analyzes the feedback accuracy of a novel ASA algorithm (Amplio Learning Technologies), in comparison to clinician judgments.

METHOD

A total of 3,584 consonant stimuli, produced by 395 American English-speaking children and adolescents with SSDs (age range: 4-18 years), were analyzed with respect to automatic classification of the ASA algorithm, clinician-ASA agreement, and interclinician agreement. Further analysis of results as related to phoneme acquisition categories (early-, middle-, and late-acquired phonemes) was conducted.

RESULTS

Agreement between clinicians and ASA classification for sounds produced accurately was above 80% for all phonemes, with some variation based on phoneme acquisition category (early, middle, late). This variation was also noted for ASA classification into "acceptable," "unacceptable," and "unknown" (which means no determination of phoneme accuracy) categories, as well as interclinician agreement. Clinician-ASA agreement was reduced for misarticulated sounds.

CONCLUSIONS

The initial findings of Amplio's novel algorithm are promising for its potential use within the context of home practice, as it demonstrates high feedback accuracy for correctly produced sounds. Furthermore, complexity of sound influences consistency of perception, both by clinicians and by automated platforms, indicating variable performance of the ASA algorithm across phonemes. Taken together, the ASA algorithm may be effective in facilitating speech sound practice for children with SSDs, even in the absence of the clinician.

Diagnosing inconsistent phonological disorder: quantitative and qualitative measures

Studies of children's consistency of word production allow identification of speech sound disorder. Inconsistent errors are reported for two groups of children: childhood apraxia of speech (CAS) due to difficulty with the motoric precision and consistency of speech movements; and inconsistent phonological disorder (IPD) attributed to impaired phonological planning. This paper describes the inconsistent productions of children with IPD in comparison to typically developing children. In two studies of suspected SSD (N = 135), 22 children pronounced ≥40% of 25 words inconsistently on three repeated trials. No participant had symptoms of CAS. They were monolingual and spoke Australian- or Irish-English. Assessment determined the proportions of words said consistently (i.e. the same across productions: all correct or with the same error) or inconsistently (i.e. differently across productions: at least one correct and one error or different errors in productions). Qualitative analyses examined error types and explored the effect of target words' characteristics on inconsistency. Children with IPD produced 52% of words with different errors. While 56% of all phoneme errors were developmental (age appropriate or delayed), atypical errors typified inconsistency: default sounds and word structure errors. Words with more phonemes, syllables and consonant clusters were vulnerable to inconsistency, but their frequency of occurrence had no effect. TD children and those with IPD had different quantitative and qualitative error profiles, confirming IPD as a diagnostic category of SSD. Qualitative analyses supported the hypothesised deficit in phonological planning of words' production for children with IPD.

Articulatory and segmental performance in children with and without speech disorder: A multiple case pilot study

This multiple case pilot study explored how nonword imitation influences articulatory and segmental performance in children with and without speech disorder. Eight children, ages 4- to 8-years-old, participated, including two children with childhood apraxia of speech (CAS), four children with phonological disorder (PD), and two children with typical development (TD). Tokens included two complexity types and were presented in random order. Minimal feedback was provided and nonwords were never associated with a referent. Kinematic and transcription data were analysed to examine articulatory variability, segmental accuracy, and segmental variability in session 1 and session 5. Descriptive statistics, percent change, effect sizes, and Pearson correlations are reported. In session 1, the two participants with CAS showed high articulatory variability, low segmental accuracy, and high segmental variability compared to the participants with PD and TD. By session 5, both participants with CAS, two with PD, and one with TD showed increased articulatory variability in the lowest complexity nonword. Segmental accuracy remained low and variability remained high for the two participants with CAS in session 5, whereas several participants with PD and TD showed improved segmental performance. Articulatory and segmental variability were not significantly correlated. The results of this study suggest that motor practice with minimal feedback and no assignment of a lexical referent can instantiate positive changes to segmental performance for children without apraxia. Positive changes to segmental performance are not necessarily related to increased articulatory control; these two processing levels can show distinct and disparate learning trajectories.

Variability, accuracy, and cross-linguistic transfer in bilingual children speaking Jamaican Creole and English

Due to the lack of normative data about bilingual speech development and limited availability of diagnostic tools optimised for this population, bilingual children under consideration for speech-language services are at an elevated risk of misdiagnosis. In the absence of validated assessment tools, speech-language pathologists may use measures of accuracy and variability of speech production to diagnose suspected speech sound disorders in bilingual children. Research in general motor development suggests that variability and accuracy may trade off in the course of maturation, whereby movement variability spikes before the transition to a more mature stage of motor control. Such variability-accuracy tradeoffs have been described in monolingual speech development but are understudied in bilingual populations, where cross-linguistic transfer occurs. This study aimed to examine variability, accuracy, and cross-linguistic transfer in the speech of 20 bilingual children speaking Jamaican Creole and English. We hypothesised that children who showed higher accuracy in their productions would also exhibit more variable speech, indicating a variability-accuracy tradeoff. The Word Inconsistency Assessment from the Diagnostic Evaluation of Articulation and Phonology was administered to measure accuracy and variability in the English context, where misdiagnosis is likely to occur. Contrary to our hypothesis, we observed that individuals with higher accuracy tended to be less variable in their productions. Future research should examine longitudinal trajectories of accuracy and variability and consider a more culturally-appropriate definition of 'accuracy' in documenting bilingual speech sound development.

Preschool children's consistency of word production

Consistency of word production contributes to carers' ability to understand children's speech. Reports of the proportion of words produced consistently by typically developing preschool children, however, vary widely from 17% to 87%. This paper examines the quantitative (consistency count) and qualitative (e.g. phonemic analysis) characteristics of word consistency in 96 children aged 36-60 months. Children named 15 pictures twice, in separate trials, in the same assessment session. The mean consistency of the production for the whole group was 82%. Older children were more consistent than younger children. Girls were more consistent than boys. Words produced correctly in one trial and in error in another may indicate resolving error patterns. Words produced in error in two different ways provided useful evidence about the nature of inconsistent word production in typically developing children. The clinical and theoretical implications are discussed.

Changes in variability during intervention for childhood apraxia of speech: implications for therapy

Typically developing children are variable in their speech production with decreasing variability indicating mastery of speech. Excessive variability which does not change over time may be an indication of unstable motor plans as often seen in children with childhood apraxia of speech (CAS). Dynamic Systems Theory (DST) provides a framework for understanding the role of variability in speech development and disorder. There are few studies that explore the impact of therapy on speech variability. This work explores the impact of therapy on perceptual speech production variability. It is a post-hoc analysis of data collected in two intervention studies of a motor-based treatment approach with children with CAS and explores DST variability effects in speech skill acquisition based on the case data from those studies. There were six participants in total across the two studies. Findings were mixed showing some non-linear changes in variability with larger changes in variability observed in participants who engaged in more extensive therapy. However, the pattern of variability change was not consistent across the participants. These findings suggest that targeting variability in therapy may be an effective way to improve the speech of children with CAS. A model for utilising variability in therapy is presented.

Speech Error Variability and Phonological Awareness in Preschoolers

PURPOSE

The purpose of this article was to investigate the relationship between speech error variability and phonological awareness.

METHOD

This article begins with a narrative review of the theoretical interpretation of speech error variability. The post hoc exploratory analysis of the relationship between speech error variability and phonological awareness included 40 children: 20 with typical speech and language and 20 with speech sound disorder and typical language. Groups were matched on gender, age, maternal education, receptive and expressive vocabulary, nonverbal intelligence, and expressive morphosyntax. Multiple regression was used to identify the best fit model for the relationship between vocabulary, speech errors, and phonological awareness.

RESULTS

Segmental variability was associated with poor phonological awareness in preschool-aged children.

CONCLUSION

Children with high levels of segmental variability have poor phonological awareness, likely due to unstable phonological representations.

When codas trump onsets: an English-speaking child with atypical phonological development before and after intervention

This case study presents an English-speaking preschooler with severely protracted phonological development (PPD) before and after two six-week blocks of intervention (36 sessions). Pre-treatment (3;8), he showed very low whole word, singleton consonant, vowel, and word shape matches. He had two major uncommon patterns: (1) higher accuracy for word-final consonants compared with word-initial (WI) and word-medial (WM); and (2) frequent substitution of onset consonants with glottals [h] or [ʔ]. Goals and treatment strategies were selected using a nonlinear phonological approach. Post-treatment, there was a notable decrease in frequency of glottal substitutions and concomitant increase in word shape, consonant, and vowel match. Pre- and post-treatment data are presented and discussed in terms of theoretical and clinical implications.

Perturbing the consistency of auditory feedback in speech

Sensory information, including auditory feedback, is used by talkers to maintain fluent speech articulation. Current models of speech motor control posit that speakers continually adjust their motor commands based on discrepancies between the sensory predictions made by a forward model and the sensory consequences of their speech movements. Here, in two within-subject design experiments, we used a real-time formant manipulation system to explore how reliant speech articulation is on the accuracy or predictability of auditory feedback information. This involved introducing random formant perturbations during vowel production that varied systematically in their spatial location in formant space (Experiment 1) and temporal consistency (Experiment 2). Our results indicate that, on average, speakers’ responses to auditory feedback manipulations varied based on the relevance and degree of the error that was introduced in the various feedback conditions. In Experiment 1, speakers’ average production was not reliably influenced by random perturbations that were introduced every utterance to the first (F1) and second (F2) formants in various locations of formant space that had an overall average of 0 Hz. However, when perturbations were applied that had a mean of +100 Hz in F1 and −125 Hz in F2, speakers demonstrated reliable compensatory responses that reflected the average magnitude of the applied perturbations. In Experiment 2, speakers did not significantly compensate for perturbations of varying magnitudes that were held constant for one and three trials at a time. Speakers’ average productions did, however, significantly deviate from a control condition when perturbations were held constant for six trials. Within the context of these conditions, our findings provide evidence that the control of speech movements is, at least in part, dependent upon the reliability and stability of the sensory information that it receives over time.

Predictors of Speech Severity and Inconsistency Over Time in Children With Token-to-Token Inconsistency

PURPOSE

The aim of this study was to describe and explain changes in severity of speech sound disorder (SSD) and token-to-token inconsistency in children with high levels of inconsistency.

METHOD

Thirty-nine children (aged 4;6-7;11 [years;months]) with SSDs and high levels of token-to-token inconsistency were assessed every 6 months for 2 years (i.e., five assessment points). Growth modeling was used to assess relations among therapy support, receptive vocabulary, severity, and inconsistency over time.

RESULTS

Children with the most severe SSDs and highest levels of token-to-token inconsistency showed the smallest improvements in speech accuracy over time. Therapy support did not predict changes in speech accuracy or token-to-token inconsistency over time. Receptive vocabulary (measured at the outset of the study) was also a significant predictor of speech accuracy and inconsistency.

CONCLUSIONS

These findings suggest that an immediate start to intervention (rather than a wait-and-see approach) is recommended for children with inconsistent speech error patterns. The results also highlight the value of developing vocabulary knowledge in addition to improving speech accuracy for some children with inconsistent speech production.

Intraword Variability in Children With Auditory Brainstem Implants: A Longitudinal Comparison With Children With Cochlear Implants

PURPOSE

Intraword variability designates the phenomenon that a particular target word is produced variably by a child at one point in the child's development. In this study, the amount of intraword variability is studied longitudinally in children with auditory brainstem implants (ABIs). Auditory brainstem implantation is a relative recent technique in pediatric hearing restoration. Therefore, little is known about the phonological development of these children's speech.

METHOD

The intraword variability is investigated in three children with ABI, in comparison to children with cochlear implants, matched on lexical development. Intraword variability is measured using relative entropy in order to take into account the frequency distribution in children's productions.

RESULT

Results showed considerable variation between the three children with ABI. Still, all children had higher levels of intraword variability in their spontaneous speech productions as compared to children with cochlear implants.

CONCLUSION

It seems that children with ABI are lagging behind their phonological development in reference to children with cochlear implants.

Facing a Clinical Challenge: Limited Empirical Support for Toddler Speech Sound Production Intervention Approaches

PURPOSE

Speech sound production intervention in early childhood is relatively rare despite empirical and theoretical support for providing this type of targeted therapy for toddlers. Challenges perpetuate the present clinical condition including those related to treatment decision making (e.g., intervention approach).

METHOD

Although there are numerous speech sound production treatment approaches appropriate for the pediatric population, a much smaller proportion are proposed to be appropriate for children under the age of 3 years. Of these, five approaches (i.e., core vocabulary, cycles, naturalist recast, stimulability, and psycholinguistic intervention) were selected for review because they can be used to treat functional speech sound disorders produced by toddlers and none required additional clinician training for implementation.

RESULTS

We found the empirical evidence supporting the use of these approaches with children under the age of 3 years scant to nonexistent.

CONCLUSIONS

Due to the lack of empirical evidence, early intervention speech-language pathologists must primarily rely on internal factors (e.g., clinician experience and client/caregiver perspectives) to support evidence-based intervention decisions in the absence of external empirical support. Clinical action steps such as careful documentation of approaches used/discontinued and associated individual client outcomes are necessary for evidence-based decision making until more robust empirical evidence is established.

Performance of Swedish children on a dynamic motor speech assessment

Purpose: This study was designed to evaluate the performance of typically developing Swedish-speaking children on DYMTA (Dynamisk Motorisk Talbedömning), a Swedish dynamic motor speech assessment.Method: Participants were 94 children, 45 boys/49 girls (9/8 multilingual), with typical oral motor, speech, and language skills, between 37 and 106 months divided into five age-groups. They performed two speech motor assessments, DYMTA-A and DYMTA-B using dynamic assessment.Result: Typically developing children show good motor speech performance on targeted speech characteristics already at the age of three. DYMTA median total score was high for all ages; 90% of maximum or above. A significant correlation with age was found for DYMTA-A (p = 0.000, r = 0.49) and DYMTA-B (p = 0.000, r = 0.77). No significant differences were found across gender or concerning being mono- or multilingual.Conclusion: DYMTA is the first Swedish assessment tool designed to identify children with CAS. The results of this study demonstrate that typically developing Swedish children perform well on DYMTA and that the test has possible utility for both mono- and multilingual children.

Speech inconsistency and its association with speech production, phonological awareness and nonword repetition skills

The purpose of this study was to investigate relationships between speech inconsistency, speech production skills, phonological awareness and nonword repetition (NWR) in 24 preschool-aged Finnish-speaking children with speech sound disorder (SSD) and in 31 children with typical speech and language development (TD). Speech inconsistency was assessed by a picture-naming task repeated three times during one assessment session. The participants' speech production skills were assessed with the Finnish Test for Phonology and a diadochokinetic (DDK) task. Phonological awareness was investigated by the tasks of Rhyme and initial syllable awareness and Syllable segmentation, and NWR by ten 2-4-syllabic nonwords. The findings indicated that the children with SSD were less accurate in speech production and NWR than the children with TD. No difference was found in phonological awareness. Among the children with SSD, speech inconsistency was correlated with accuracy in overall speech production, DDK task, and NWR. Among the children with TD, speech inconsistency was correlated with accuracy in overall speech production, partly with phonological awareness, and with NWR. The results provide support for the idea that when assessing speech inconsistency in children with SSD, a process-oriented approach may be needed in order to obtain an adequately broad picture of their skill profiles.

Intraword Variability in French-Speaking Monolingual and Bilingual Children

Purpose This study examines intraword variability in 40 typically developing French-speaking monolingual and bilingual children, aged 2;6-4;8 (years;months). Specifically, it measures rate of intraword variability and investigates which factors best account for it. They include child-specific ones such as age, expressive vocabulary, gender, bilingual status, and speech sound production ability, and word-specific factors, such as phonological complexity (including number of syllables), phonological neighborhood density (PND), and word frequency. Method A variability test was developed, consisting of 25 words, which differed in terms of phonological complexity, PND, and word frequency. Children produced three exemplars of each word during a single session, and productions of words were coded as variable or not variable. In addition, children were administered an expressive vocabulary test and two tests tapping speech motor ability (oral motor assessment and diadochokinetic test). Speech sound ability was also assessed by measuring percent consonants correct on all words produced by the children during the session. Data were entered into a binomial logistic regression. Results Average intraword variability was 29% across all children. Several factors were found to predict intraword variability including age, gender, bilingual status, speech sound production ability, phonological complexity, and PND. Conclusions Intraword variability was found to be lower in French than what has been reported in English, consistent with phonological differences between French and English. Our findings support those of other investigators in indicating that the factors influencing intraword variability are multiple and reflect sources at various levels in the speech processing system.

Lexical-Semantic Cues Induce Sound Pattern Stability in Children With Developmental Language Disorder

Purpose When learning novel word forms, preschoolers with developmental language disorder (DLD; also known as specific language impairment) produce speech targets inaccurately and with a high degree of intraword variability. The aim of the current study is to specify whether and how layering lexical-semantic information onto novel phonological strings would induce increased organization of sound production patterns. Method Twenty-one preschoolers with DLD and 21 peers with typical language (ranging in age from 4;1 to 5;11 [years;months]) imitated multiple renditions of novel words, half with (i.e., words) and half without (i.e., nonwords) a linked visual referent. Methods from network science were used to assess the stability and patterning of syllable sequences. Sound accuracy was also measured. Results Children with DLD were less accurate and more variable than their typical peers. However, once word forms were associated with a visual referent, network stability, but not accuracy, improved for children with DLD. Conclusions Children with DLD showed significant word form deficits as they acquired novel words and nonwords. The inclusion of a meaningful referent resulted in increased sound sequence stability, suggesting that lexical-semantic information provides a bootstrap for phonological organization in children with DLD.

Individual variability in auditory feedback processing: Responses to real-time formant perturbations and their relation to perceptual acuity

In this study, both between-subject and within-subject variability in speech perception and speech production were examined in the same set of speakers. Perceptual acuity was determined using an ABX auditory discrimination task, whereby speakers made judgments between pairs of syllables on a /ɛ/ to /æ/ acoustic continuum. Auditory feedback perturbations of the first two formants were implemented in a production task to obtain measures of compensation, normal speech production variability, and vowel spacing. Speakers repeated the word "head" 120 times under varying feedback conditions, with the final Hold phase involving the strongest perturbations of +240 Hz in F1 and -300 Hz in F2. Multiple regression analyses were conducted to determine whether individual differences in compensatory behavior in the Hold phase could be predicted by perceptual acuity, speech production variability, and vowel spacing. Perceptual acuity significantly predicted formant changes in F1, but not in F2. These results are discussed in consideration of the importance of using larger sample sizes in the field and developing new methods to explore feedback processing at the individual participant level. The potential positive role of variability in speech motor control is also considered.

Variability across repeated productions in bilingual children speaking Jamaican Creole and English

PURPOSE

Previous work suggests that variability across repeated productions of the same word may be useful in diagnosing speech sound disorder (SSD) in bilingual children. However, there is debate over what level of variability in transcribed productions should be considered typical even in monolingual speech development. High variability in the input represents a factor that could promote increased production variability in bilinguals. For this reason, the current study examines transcription-based token-to-token variability in bilingual children speaking Jamaican Creole (JC) and English.

METHOD

Twenty-five bilingual children aged 3;4-5;1 and twenty-five monolingual children aged 2;9-4;1 from a previous study were recorded producing eleven items in three repetitions.

RESULT

Contrary to our hypothesis, bilingual children showed similar rates of token-to-token variability compared to the monolingual children. In a separate analysis of bilingual data across languages, bilingual children were more variable in JC compared to English productions.

CONCLUSION

The difference between language contexts suggests that creole languages, which exist on a usage continuum, may be associated with increased variability in production. Our findings suggest that token-to-token production variability may be of similar clinical utility for bilingual and monolingual populations.

Speech sound development in typically developing 2-7-year-old Dutch-speaking children: A normative cross-sectional study

BACKGROUND

Dutch is a West-Germanic language spoken natively by around 24 million speakers. Although studies on typical Dutch speech sound development have been conducted, norms for phonetic and phonological characteristics of typical development in a large sample with a sufficient age range are lacking.

AIM

To give a detailed description of the speech sound development of typically developing Dutch-speaking children from 2 to 7 years.

METHODS & PROCEDURES

A total of 1503 typically developing children evenly distributed across the age range of 2;0-6;11 years participated in this normative cross-sectional study. The picture-naming task of the Computer Articulation Instrument (CAI) was used to collect speech samples. Speech development was described in terms of (1) percentage consonants correct-revised (PCC-R) and percentage vowels correct (PVC); (2) consonant, vowel and syllabic structure inventories; (3) degrees of complexity (phonemic feature hierarchy); and (4) phonological processes.

OUTCOMES & RESULTS

A two-way mixed analysis of variance (ANOVA) confirmed a significant increase in the number of PCC-R and PVC between the ages of 2;0 and 6;11 years (p < 0.001). The consonant inventory was found to be complete at 3;7 years of age for the syllable-initial consonants, with the exception of the voiced fricatives /v/ and /z/, and the liquid /r/. All syllable-final consonants were acquired before age 4;4 years. At age 3;4 years, all children had acquired a complete vowel inventory, and at age 4;7 years they produced most syllable structures correctly, albeit that the syllable structure CCVCC was still developing. All phonological contrasts were produced correctly at 3;8 years of age. Children in the younger age groups used more phonological simplification processes than the older children, and by age 4;4 years, all had disappeared, except for the initial cluster reduction from three to two consonants and the final cluster reduction from two to one consonant.

CONCLUSIONS & IMPLICATIONS

This paper describes a large normative cross-sectional study of Dutch speech sound development which, in clinical practice, can help Dutch speech-language pathologists to differentiate children with delayed or disordered speech development from typically developing children. What this paper adds What is already known on this subject In recent years many studies have been conducted worldwide to investigate speech sound development in different languages, including several that explored the typical speech sound development of Dutch-speaking children, but none of these latter studies explored both phonetic and phonological progress within a comprehensive age range and a large sample that is representative of the Dutch population. What this study adds to existing knowledge This study serves to fill this gap by providing normative cross-sectional results obtained in 1503 typically developing Dutch-speaking children aged between 2;0 and 6;11 years on informative parameters of speech development: PCC-R and PVC, consonant, vowel and syllabic structure inventories, degrees of complexity (phonemic feature hierarchy), and phonological simplification processes. What are the potential or actual clinical implications of this work? The detailed description of typical Dutch speech sound development provides speech-language pathologists with pertinent information to determine whether a child's speech development progresses typically or is delayed or disordered.

Intra-word accuracy and consistency in Finnish-speaking children with speech sound disorder compared to their typically developing peers

This study examined intra-word accuracy and consistency in 32 preschool-aged Finnish-speaking children with speech sound disorder (SSD) compared to their typically developing (TD) age- and gender-matched peers. Accuracy and consistency of speech production were assessed by a picture-naming task repeated three times in one assessment session. Responses were classified into four categories: 1) consistently correct, 2) consistently incorrect, 3) variable with hits (when a child's variable responses included at least one matched with the adult target), and 4) variable with no hits (when responses included at least two different response types without the matched adult target). In addition, relationships between intra-word accuracy and consistency and children's receptive vocabulary knowledge and articulatory ability based on spontaneous speech samples were investigated. The findings showed that the children with SSD produced significantly more often 'consistently incorrect' and 'variable with no hits' responses than the TD children. There was a significant negative correlation between 'variable with no hits' responses and receptive vocabulary knowledge and articulatory abilities among the children with SSD. As intra-word accuracy and consistency has not previously been studied in Finnish children with SSD, the findings highlighted the need for drafting guidelines for assessment and intervention by paying close attention to high intra-word variability without correct word forms already from age three onwards.

Development and measurement of psychometric properties of the Persian test of speech consistency in children with typical development

The current research pursues the study of developing the Persian test of speech consistency and investigating speech consistency in normally developing children in Iran. After developing the Persian test of speech consistency, the obtained speech samples of 317 participants (163 girls and 154 boys) were analyzed. This test of consistency includes 27 items. Experts' consensus over the characteristics of the Persian test of speech consistency was above 85%. Different age groups had statistically significant differences for the mean scores of the variable responses (p < .001), consistent correct (p < .001), and consistent incorrect responses (p = .007) in the Persian test of speech consistency. Also, there was a high value for the inter-rater reliability (ICC = .88, p < .001) as well as the moderate value for the test-retest reliability (ICC = .89, p < .001). The Persian test of speech consistency is regarded as a reliable and valid scale for measuring the speech consistency in Persian-speaking children. Future studies are proposed to investigate the speech consistency in Persian-speaking children with various kinds of speech sound disorders.

Speech Production Accuracy and Variability in Monolingual and Bilingual Children With Cochlear Implants: A Comparison to Their Peers With Normal Hearing

Purpose This study investigates consonant and vowel accuracy and whole-word variability (also called token-to-token variability or token-to-token inconsistency) in bilingual Spanish-English and monolingual English-speaking children with cochlear implants (CIs) compared to their bilingual and monolingual peers with normal hearing (NH). Method Participants were 40 children between 4;6 and 7;11 (years;months; M _age = 6;2), n = 10 each in 4 participant groups: bilingual Spanish-English with CIs, monolingual English with CIs, bilingual Spanish-English with NH, and monolingual English with NH. Spanish and English word lists consisting of 20 words of varying length were generated, and 3 productions of each word were analyzed for percent consonants correct, percent vowels correct, and the presence of any consonant and/or vowel variability. Results Children with CIs demonstrated lower accuracy and more whole-word variability than their peers with NH. There were no differences in rates of accuracy or whole-word variability between bilingual and monolingual children matched on hearing status, and bilingual children had lower accuracy and greater whole-word variability in English than in Spanish. Conclusions High rates of whole-word variability are prevalent in the speech of children with CIs even after many years of CI experience, and bilingual language exposure does not appear to negatively impact phonological development in children with CIs. Contributions to our understanding of underlying sources of speech production variability and clinical implications are discussed.

Profiling Speech Sound Disorders for Clinical Validation of the Computer Articulation Instrument

Purpose The current article presents data from 2 studies on clinical groups of children referred for speech assessment. The aims of these studies are to validate the Computer Articulation Instrument (CAI) with the known-group validation method and to determine the differential diagnostic power of the resulting speech profiles. Method Study 1 examined known-group validity by comparing the scores of 93 children diagnosed with speech-language difficulties on the picture naming (PN) task of the CAI with intelligibility judgments given by speech-language pathologists. In Study 2, the speech profiles of 41 children diagnosed with speech sound disorders (SSDs), consisting of 4-6 factor scores extracted from the 4 tasks of the CAI, namely, PN, nonword imitation (NWI), word and nonword repetition, and maximum repetition rate (MRR), were validated against clinical judgments of severity of the SSD given by speech-language pathologists. Results In Study 1, a repeated-measures analysis of variance revealed a significant effect of intelligibility level on the PN performance of the CAI and there were highly significant correlations between intelligibility and PN performance in the expected direction. Neither intelligibility level nor PN performance was related to nonverbal intelligence and language scores. The analysis of variance and a series of t tests in Study 2 revealed significant differences between the moderate and severe groups for the CAI factors based on PN and NWI and the bisyllabic and trisyllabic sequences of MRR, but not for the factor word and nonword proportion of whole-word variability based on word and nonword repetition, and the monosyllabic sequences of MRR. These results suggest that, especially, the tasks PN, NWI, and the bisyllabic and trisyllabic sequences of MRR are most sensitive for diagnosing SSDs. Conclusions The findings of these 2 studies support the known-group validity of the CAI. Together with the results of a previous study of our group on reliability and validity ( van Haaften et al., 2019 ), we can conclude that the CAI is a reliable and valid tool for assessment of children with SSDs.

The Psychometric Evaluation of a Speech Production Test Battery for Children: The Reliability and Validity of the Computer Articulation Instrument

Purpose The aims of this study were to assess the reliability and validity of the Computer Articulation Instrument (CAI), a speech production test battery assessing phonological and speech motor skills in 4 tasks: (1) picture naming, (2) nonword imitation, (3) word and nonword repetition, and (4) maximum repetition rate (MRR). Method Normative data were collected in 1,524 typically developing Dutch-speaking children (aged between 2;0 and 7;0 [years;months]). Parameters were extracted on segmental and syllabic accuracy (Tasks 1 and 2), consistency (Task 3), and syllables per second (Task 4). Interrater reliability and test-retest reliability were analyzed using subgroups of the normative sample and studied by estimating intraclass correlation coefficients (ICCs). Construct validity was investigated by determining age-related changes of test results and factor analyses of the extracted speech measures. Results ICCs for interrater reliability ranged from sufficient to good, except for percentage of vowels correct of picture naming and nonword imitation and for the MRRs for bisyllabic and trisyllabic items. The ICCs for test-retest reliability were sufficient (picture naming, nonword imitation) to insufficient (word and nonword repetition, MRR) due to larger-than-expected normal development and learning effects. Continuous norms showed developmental patterns for all CAI parameters. The factor analyses revealed 5 meaningful factors: all picture-naming parameters, the segmental parameters of nonword imitation, the syllabic structure parameters of nonword imitation, (non)word repetition consistency, and all MRR parameters. Conclusion Its overall sufficient to good psychometric properties indicate that the CAI is a reliable and valid instrument for the assessment of typical and delayed speech development in Dutch children in the ages of 2-7 years.

Intra-word consistency and accuracy in Finnish children aged 3-6 years

This study examined intra-word consistency and accuracy in typically developing Finnish children and their relation to children's vocabulary size and phonological skills. A total of 80 typically developing Finnish children aged 3;0 to 6;11 were asked to name 20 words three separate times during a single assessment session. Responses were classified into four categories: 1) consistently correct productions, 2) consistently incorrect productions, 3) variable productions with hits (variable productions including at least one matched adult target), and 4) variable productions with no hits. The results revealed that 5- and 6-year-old children produced significantly more often consistently correct responses than younger children. However, even for the 3- and 4-year old children the most frequent response type was consistently correct production. Between these two youngest age groups (3 and 4), the only significant difference was in consistently incorrect responses, which the 3-year-olds produced more often than the older children. There was a significant negative correlation between consistently incorrectly produced words and children's phonological skills, but no other relationships were found. The results indicate that when assessing children with speech sound disorder (SSD), Finnish clinicians need to take into account the fact that even 3-year-old typically developing children generally produce words correctly, either consistently or inconsistently.

Single word test for the assessment of speech sound production in Persian speaking children: Development, validity and reliability

OBJECTIVES

Single word tests are used frequently to determine clients' speech sound errors. These tools are user-friendly and popular for speech and language pathologists. The aim of this study was to design and validate a single word test for the assessment of speech sound production for Persian speaking children.

METHODS

The present study included two phases. In phase I, test material was developed. Psychometric properties were evaluated in phase II. In the next phase, 525 typically developing Persian-speaking children with the age range of 3-5 years old were studied. Statistical Package for the Social Sciences, version 24.0 (SPSS, Inc., Chicago, IL) was used for statistical analysis of this study. The significance level was set at (p < 0.05). Pilot study was performed by administrating the test on 25 typically developing children, construct validity: by administrating the test on 400 typically developing children and the comparison of performance of the children in 4 age groups (discriminative validity regarding age and by administration of this test and phonetic subtest of Persian version of diagnostic evaluation of articulation and phonology on 100 children (convergent validity)). Inter-rater reliability was performed by transcription and scoring of samples of 25 children and calculation of Intra Correlation Coefficient (ICC) was calculated. Test-retest was completed by administrating the test two times on 30 children with two weeks intervals. Internal consistency was achieved by the calculation of the correlation of the items of test.

RESULTS

The final version of the test includes 70 target words for assessment of the consonants in three positions, vowels in medial position and consonant clusters (CVCC). There was 80% or more than it for the percentage agreement between experts for the content validity. There wasn't any significant difference between experts' responses about items of the test. 4 pictures were revised based on children's responses for the pilot study. All of the reliability values (test-re test, internal consistency and inter-rater reliability) were higher than 0.85. There was a significant difference between the four age groups for the mean value of Persian single word test for speech sound production (p < 0.0001). There was a high correlation between the score of this instrument and the scores of participants in the Phonetic sub-test of the Persian version of Diagnostic evaluation of articulation and phonology(r = 0.934, p < 0.0001).

CONCLUSION

It seems that the Persian Speech sound Production Test is a reliable and valid tool that can be used to measure speech sound errors for Persian speaking children.

An Application of Network Science to Phonological Sequence Learning in Children With Developmental Language Disorder

PURPOSE

Network science has been a valuable tool in language research for investigating relationships between complex linguistic elements but has not yet been applied to sound sequencing in production. In the present work, we used standard error-based accuracy and articulatory kinematic approaches as well as novel measures from network science to evaluate variability and sequencing errors in speech production in children with developmental language disorder (DLD; aka specific language impairment).

METHOD

Twelve preschoolers with DLD and 12 age-matched controls participated in a 3-day novel word learning study. Transcription and articulatory movement data were collected to measure accuracy and variability of productions, and networks of speech productions were generated to analyze syllable co-occurrence patterns.

RESULTS

Results indicated that children with DLD were less accurate than children with typical language at the segmental level. Crucially, these findings did not align with performance at the articulatory level, where there were no differences in movement variability between children with DLD and those with typical language. Network analyses revealed characteristics that were not captured by standard measures of phonetic accuracy, including a larger inventory of syllable forms, more connections between the forms, and less consistent production patterns.

CONCLUSIONS

Network science provides significant insights into phonological learning trajectories in children with DLD and their typically developing peers. Importantly, errors in word production by children with DLD do not surface as a result of weakness in articulatory control. Instead, results suggest that speech errors in DLD may relate to deficits in sound sequencing.

Stimulus Characteristics of Single-Word Tests of Children's Speech Sound Production

Purpose

This clinical focus article provides readers with a description of the stimulus characteristics of 12 popular tests of speech sound production.

Method

Using significance testing and descriptive analyses, stimulus items were compared in terms of the number of opportunities for production of all consonant singletons, clusters, and rhotic and nonrhotic vowels of Standard American English; phonetic/phonological and structural complexity; and the presence of bound morphemes.

Results

The tests varied widely in terms of the number of opportunities for production of consonant singletons, clusters, and rhotic and nonrhotic vowels. Most of the tests included only 1 opportunity, scored or unscored, to produce a majority of the consonant singletons in each word position. Only 3 of the tests included stimulus items with 3-element clusters. The majority contained limited opportunities to produce 3- or 4-syllable stimulus items. The tests provided sufficient opportunities for production of most vowels, although most did not score vowels. The tests differed significantly in the complexity of their stimulus items. Most, however, contained a negligible number of items that, with the addition of a bound morpheme, resulted in a word-final cluster.

Conclusion

Most of the tests elicit an inadequate sample with which to conduct a comprehensive phonological analysis.

An exploratory study of the influence of load and practice on segmental and articulatory variability in children with speech sound disorders

This exploratory treatment study used phonetic transcription and speech kinematics to examine changes in segmental and articulatory variability. Nine children, ages 4 to 8 years old, served as participants, including two with childhood apraxia of speech (CAS), five with speech sound disorder (SSD) and two who were typically developing. Children practised producing agent + action phrases in an imitation task (low linguistic load) and a retrieval task (high linguistic load) over five sessions. In the imitation task in session one, both participants with CAS showed high degrees of segmental and articulatory variability. After five sessions, imitation practice resulted in increased articulatory variability for five participants. Retrieval practice resulted in decreased articulatory variability in three participants with SSD. These results suggest that short-term speech production practice in rote imitation disrupts articulatory control in children with and without CAS. In contrast, tasks that require linguistic processing may scaffold learning for children with SSD but not CAS.

Comprehensive Assessment of Speech Sound Production in Preschool Children

This paper describes a comprehensive speech sound assessment for preschool children suspected of having a speech sound disorder (SSD). Recommended components include standardized single-word testing, additional single-word testing, connected speech sampling, phonological analyses, stimulability testing, and inconsistency testing. While data collection and some cursory analyses take place during the evaluation session, allowing the speech-language pathologist (SLP) to share key information with the parents/caregivers, much of the in-depth analysis takes place later. Since most preschool children's SSDs are phonological in nature, a phonological approach to analysis, target selection, and treatment is required. Two examples of phonological analyses, a place-voice-manner (PVM) analysis and an error pattern analysis, are discussed. Both allow the SLP to identify patterns of difficulty in the child's speech with regards to the place, voicing, and/or manner characteristics of target consonants. Phonological analyses can be performed using the child's single-word and connected speech samples. This information, along with the results from the stimulability and inconsistency testing, will allow the SLP to gain a complete picture of the child's speech sound abilities and difficulties, determine prognosis for change, and identify treatment targets.

Predictors of token-to-token inconsistency in preschool children with typical speech-language development

The purpose of this study was to examine potential concurrent predictors and replicate rates of token-to-token inconsistency (inconsistency in repeated productions of the same word) in 43 children with typical speech-language development, ages 2;6 to 4;2. A standard linear regression was used to determine which variables, if any, among age, expressive and receptive vocabulary, and speech sound production abilities predicted token-to-token inconsistency. Inconsistency rates in children from one research site, reported elsewhere, were compared to rates in children from a second research site. The results revealed that expressive vocabulary was the only significant predictor of token-to-token inconsistency in these children. Furthermore, inconsistency rates were similarly high across the two research sites. The findings are discussed in terms of their implications for our theoretical understanding of token-to-token inconsistency and its role in the differential diagnosis of speech sound disorders in children.