Consonant Production Research Articles

Acquisition of /s/ clusters in English-speaking children with phonological disorders

Two member onset consonant clusters with /s/ as the first member (#sC onsets) behave differently from other double onset consonant clusters in English. Phonological explanations of children's consonant cluster production have been posited to predict children's speech acquisition. The aim of this study was to consider the role of the Sonority Sequencing Principle (SSP), homorganicity, headedness, and factorial typology in the explanation of productions of consonant clusters by children with phonological disorders. Thirty monolingual English-speaking children with phonological disorders produced words commencing with #sC: /s/+stop (/sT/), /s/+nasal (/sN/), /sl/, and /sw/. There was wide individual variation between participants. Overall, there was an increase in accuracy of consonant cluster production as the sonority indices of the second element of the cluster increased: there was significantly greater accuracy of /sl/ than /sN/ and significantly greater accuracy of /sN/ than /sT/. However, /sw/ targets only followed the SSP for phonologically accurate (but not phonetically accurate) productions. Correct renditions justified the binary grouping of the SSP-following vs SSP-violating separation. Homorganicity of the cluster was not a factor in determining relative accuracy of the targets. The percentage of correct renditions justified the /s/+[−continuant] vs /s/+[+continuant] binary separation. There were several counterexamples of predictions of the headedness approach. Thus, sonority and factorial typology were found to be useful in predicting /s/ consonant cluster acquisition of children with phonological disorders.

A multi-dimensional approach to gradient change in phonological acquisition: A case study of disordered speech development

The purpose of the current study is to document phonological change from a multidimensional perspective for a 3-year-old boy with phonological disorder by comparing three measures: (1) accuracy of consonant productions, (2) dynamic assessment, and (3) acoustic analysis. The methods included collecting a sample of the targets /s, ʃ, tʃ, and dʒ/ produced in single words and repeated over time. The samples were analysed using phonetic transcription and acoustic measures of duration, spectral mean, and spectral variance. A dynamic assessment was administered that showed change in response to cues and linguistic environments using a 15-point scale. The results from the three measures were compared for gradient change and evidence of covert contrasts. In conclusion, gradient change was illustrated across the three measures and contrasts were evident in the child's phonological system. Acoustic measures were most sensitive, followed by dynamic assessment; however, accuracy scores based on phonetic transcription showed little to no change for some targets.

Aeroacoustics of voiceless fricatives: An in-vitro investigation on simplified vocal tract geometries.

Production of fricatives consonants is a complex aeroacoustical problem involving the interaction of turbulent airflow with the particular geometry of the vocal tract. The current study introduces a simplified mechanical static vocal tract including a tongue replica and a rectangular thin obstacle downstream of the constriction formed by the tongue and the upper tract wall. First, pressure of the vocal tract flow and far-field noise are measured for different entrance volume velocities, longitudinal tongue positions, and obstacle heights. Changing the geometrical parameters induces spectral noticeable changes and, particulary, when the ratio obstacle height/tract height is close to 1, spectra are shaped like those of sibilant fricatives. Next, velocity-turbulence measurements in the same conditions by means of hot film anemometry are realized, which permits to find relations between aerodynamics and previous acoustical observations. It will also complete pressure data for the validation of future vocal tract flow models, which could serve for fricatives synthesis applications.

Communication disorders in individuals with cleft lip and palate: An overview

ABSTRACTThe need for an interdisciplinary approach in the comprehensive management of individuals with cleft lip and palate is well recognized. This article provides an introduction to communication disorders in individuals with cleft lip and palate for members of cleft care teams. The speech pathologist is involved in identifying those infants who are at risk for communication disorders and also for initiating early intervention to prevent or mitigate communication disorders caused by the cleft. Even with early cleft repair, some children exhibit ‘cleft palate speech’ characterized by atypical consonant productions, abnormal nasal resonance, abnormal nasal airflow, altered laryngeal voice quality, and nasal or facial grimaces. These manifestations are evaluated to identify those that (a) are developmental, (b) can be corrected through speech therapy alone, and, (c) those that may require both surgery and speech therapy. Speech is evaluated perceptually using several types of stimuli. It is important to identify compensatory and obligatory errors in articulation. When velopharyngeal dysfunction is suspected, the assessment should include at least one direct measure such as nasoendoscopy or videofluoroscopy. This provides information about the adequacy of the velopharyngeal valve for speech production, and is useful for planning further management of velopharyngeal dysfunction. The basic principle of speech therapy in cleft lip and palate is to establish the correct placement of the articulators and appropriate air flow. Appropriate feedback is important during therapy for establishing the correct patterns of speech.

Foreign accent syndrome due to conversion disorder: Phonetic analyses and clinical course

We describe the case of a 36-year-old native speaker of English who began using a foreign accent after abrupt onset of problems involving multiple sensory and motor functions. Neurological and neuroradiological examinations were within normal limits and no organic explanation for the difficulties could be identified. After eight months, the patient made a full recovery, allowing a detailed comparison between the speech patterns displayed during the period of foreign accent and those of her typical speech. Perceptual and acoustic analyses showed specific changes in vowel and consonant production and in intonation and stress patterns during the accented speech. These changes were similar to those described in the literature for patients with foreign accent syndrome following left cerebral hemisphere lesions. A review of presenting symptoms and clinical course of our case, however, indicated strong evidence for a conversion disorder. This case demonstrates that a psychogenic etiology for foreign accent syndrome should sometimes be considered and that the prognosis for recovery, including spontaneous remission, may be good in such cases. Differential diagnosis between psychogenic and neurogenic etiologies is discussed relative to the case presentation, history, course, and recovery.

Acoustic and spectral patterns in young children’s stop consonant productions

The aim of this study was to examine the acoustic and spectral patterns of stop articulation in the speech of pre-pubescent children. A set of voiceless stop consonants, /ptk/, produced by a group of adults and typically developing children 3-5 years of age were examined in terms of multiple acoustic and spectral parameters. Findings indicated that, with the exception of spectral kurtosis, the acoustic and spectral characteristics of the stop productions varied significantly as a function of place of articulation and vowel context. Sex-specific differences in spectral slope, mean, and skewness were found for the 5-year-old and adult speakers. Such differences in adult speakers can be explained in part by variation in vocal tract size across the sex of the speaker; however, vocal tract dimorphism is typically not present in pre-pubescent children. Thus, the findings of this study provide some support that sex-specific differences in the speech patterns of young children may be associated with learned or behavioral factors, such as patterns of obstruent articulation that depend in part on a culturally determined male-female archetype.

Chinese Malaysian English Phonology

Malaysian English (MalE) has gained recognition as one of the New Englishes and is now developing into a mature variety with its own pronunciation. This paper represents the first attempt at an auditory quantitative description of MalE spoken by a group of ten Malaysian Chinese adults. It is appropriate to consider the English of Chinese Malaysians as a significant variety of MalE because Chinese form the second largest ethnic group in Malaysia. Historically, a group of ethnic Chinese in Malaysia was the numerically dominant urban group who attended English-medium schools and used English as their dominant language. Today, many Chinese in Malaysia speak English as a first language. The present study investigates features of the consonant and vowel production of these adults. The consonant and vowel inventories are considered as well as phonological features. Where relevant, the MalE results are compared with other varieties of English. The findings of this study are important for linguists, speech-language pathologists, English language teachers and policy makers in their respective fields of work.

Accelerated three‐dimensional upper airway MRI using compressed sensing

In speech-production research, three-dimensional (3D) MRI of the upper airway has provided insights into vocal tract shaping and data for its modeling. Small movements of articulators can lead to large changes in the produced sound, therefore improving the resolution of these data sets, within the constraints of a sustained speech sound (6-12 s), is an important area for investigation. The purpose of the study is to provide a first application of compressed sensing (CS) to high-resolution 3D upper airway MRI using spatial finite difference as the sparsifying transform, and to experimentally determine the benefit of applying constraints on image phase. Estimates of image phase are incorporated into the CS reconstruction to improve the sparsity of the finite difference of the solution. In a retrospective subsampling experiment with no sound production, 5x and 4x were the highest acceleration factors that produced acceptable image quality when using a phase constraint and when not using a phase constraint, respectively. The prospective use of a 5x undersampled acquisition and phase-constrained CS reconstruction enabled 3D vocal tract MRI during sustained sound production of English consonants /s/, /integral/, /l/, and /r/ with 1.5 x 1.5 x 2.0 mm(3) spatial resolution and 7 s of scan time.

Rapid three‐dimensional magnetic resonance imaging of vocal tract shaping using compressed sensing.

Conventional 3D magnetic resonance imaging (MRI) of vocal tract during sustained sound production takes prohibitively long and requires repetitions of the same articulation with pauses of the scan. This can produce image misregistration artifacts possibly due to different positioning of the jaw, tongue, and lips at each repetition. Within a scan time limit of 6–10 seconds, a duration practical for sustained sound production, it is desirable to accelerate high‐resolution 3D imaging by undersampling 3D k‐space. In this study, compressed sensing theory was adopted to achieve the acceleration by incoherent undersampling of 3D k‐space and minimum L1‐norm reconstruction. The increase in transform sparsity was exploited by constraining image phase in which rapid phase variation is expected in air‐tissue boundaries due to large magnetic susceptibility difference. Vocal tract volume of interest was imaged during sustained sound production of English consonants /s/, /sh/, /r/, and /l/. Vocal tract area functions we...

Gradient measures of children’s speech production: Visual analog scale and equal appearing interval scale measures of fricative goodness.

Cross-sectional and longitudinal studies of speech-sound development utilizing phonetic transcription often show an apparently discontinuous acquisition of speech sounds. Instrumental studies, in contrast, suggest that children acquire speech-sound contrasts gradually. An ideal perceptual-rating measure of children’s production should capture this gradient change in production, correlate well with acoustic data, and be fast and easy both to administer and to score. A previous experiment in our laboratory compared three methods of collecting continuous judgments of children’s consonant productions of /s/ and /∫/: Of the three, visual analog scaling (VAS) correlated best with acoustic parameters. However, as was administered in that experiment, VAS allowed only two-way comparisons between phonemes. To determine whether VAS could be used for multiple-way comparisons, two experiments were conducted. In the first, participants first made a forced choice between two phonemes, then used VAS to make a judgment of the goodness of the phoneme, from perfect to bad. A second experiment was conducted using a seven-point EAI scale in place of the VAS. The results will be correlated with acoustic data as in the previous experiment and will further our knowledge of optimal methods for measuring children’s speech production perceptually.

Measuring sensitivity to short‐term deviations in acoustic cue correlation.

Listeners are sensitive to correlations among the multiple probabilistic acoustic cues that define speech categories. In English stop consonant productions, for example, fundamental frequency (f0) is strongly correlated with voicing. Reflecting this regularity, perception of syllables varying in voice onset time is shifted with changes in f0. Such sensitivity to the long‐term regularities of a language must be balanced with enough flexibility that speech perception is able to accommodate deviations from these regularities, such as those that may arise variations from idiolect, dialect, or accented speech. The present experiments manipulate short‐term acoustic cue correlations experienced in online perception to investigate the interplay between sensitivity to long‐term and short‐term acoustic cue correlation. Using overt categorization and eyetracking, the present results indicate that speech categorization is influenced by local shifts in acoustic cue correlations that deviate from long‐term regularities of English. These experiments further examine the time course of this short‐term learning and the degree to which it generalizes. The data suggest that listeners continually monitor speech input for regularity and tune online speech perception in relation to these regularities.

A preliminary study of jaw movement in Arrernte consonant production

This study presents jaw movement data from Central Arrernte, an Australian Aboriginal language with six places of articulation in the stop series, including four coronal places of articulation. The focus of the study is on jaw consonant targets, and on the opening and closing movements of the jaw. As a point of comparison, data are also presented for English, a language with three places of articulation in the stop series. In line with previous results for English, jaw position in Arrernte is lowest for the velar /k/. The apico-post-alveolar (retroflex) /ʈ/, which is not found in English, has a jaw position almost as low as /k/. By contrast, the lamino-alveo-palatal /c/, which is also not found in English, has the highest jaw position. The remaining coronal consonants in Arrernte, /t/ (apico-alveolar and lamino-dental, respectively), show intermediate jaw positions, with differences between speakers. In terms of the kinematic measures examined (namely, variability in distance, duration and velocity of opening and closing movements), results show no consistent differences between English and Arrernte jaw movement.

Estimation of Place of Articulation During Stop Closures of Vowel–Consonant–Vowel Utterances

Production of vowel-oral stop consonant-vowel utterances involves movement of articulators from the articulatory position of the initial vowel towards that of the oral stop closure, and then to that of the final vowel. As the closure segments have zero or low signal energy, linear predictive coding (LPC)-based estimation of vocal tract shape fails during stop closure. This paper reports a technique for estimation of place of articulation during stop closures by performing bivariate polynomial modeling on vocal tract area values during transition segments preceding and following the closure. The technique with second-degree polynomial modeling was found to be suitable for estimating the place of maximum constriction during stop closure segments of vowel-consonant-vowel utterances with bilabial, alveolar, and velar stops. The estimated places compared well with the actual constriction locations observed from the articulatory data. The technique may be useful for improving effectiveness of speech-training aids for production of stop consonants by providing visual feedback of the estimated place of articulation.

Communication disorders in individuals with cleft lip and palate: An overview.

The need for an interdisciplinary approach in the comprehensive management of individuals with cleft lip and palate is well recognized. This article provides an introduction to communication disorders in individuals with cleft lip and palate for members of cleft care teams. The speech pathologist is involved in identifying those infants who are at risk for communication disorders and also for initiating early intervention to prevent or mitigate communication disorders caused by the cleft. Even with early cleft repair, some children exhibit ‘cleft palate speech’ characterized by atypical consonant productions, abnormal nasal resonance, abnormal nasal airflow, altered laryngeal voice quality, and nasal or facial grimaces. These manifestations are evaluated to identify those that (a) are developmental, (b) can be corrected through speech therapy alone, and, (c) those that may require both surgery and speech therapy. Speech is evaluated perceptually using several types of stimuli. It is important to identify compensatory and obligatory errors in articulation. When velopharyngeal dysfunction is suspected, the assessment should include at least one direct measure such as nasoendoscopy or videofluoroscopy. This provides information about the adequacy of the velopharyngeal valve for speech production, and is useful for planning further management of velopharyngeal dysfunction. The basic principle of speech therapy in cleft lip and palate is to establish the correct placement of the articulators and appropriate air flow. Appropriate feedback is important during therapy for establishing the correct patterns of speech.

Kinematic investigation of lingual movement in words of increasing length in acquired apraxia of speech

The current study aimed to use electromagnetic articulography (EMA) to investigate the effect of increasing word length on lingual kinematics in acquired apraxia of speech (AOS). Tongue‐tip and tongue‐back movement was recorded for five speakers with AOS and a concomitant aphasia (mean age = 53.6 years; SD = 12.60) during target consonant production (i.e. /t, s, k/ singletons; /kl, sk/ clusters), for one and two syllable stimuli. The results obtained for each of the participants with AOS were individually compared to those obtained by a control group (n = 12; mean age = 52.08 years; SD = 12.52). Results indicated that the participants with AOS exhibited longer movement durations and, in some instances, larger tongue movements during consonant singletons and consonant cluster constituents embedded within mono‐ and multisyllabic utterances. Despite this, two participants with AOS exhibited a word length effect that was comparable with the control speakers, and possibly indicative of an intact phonological system.

An articulatory view of Kinyarwanda coronal harmony

Coronal harmony in Kinyarwanda causes alveolar fricatives to become postalveolar preceding a postalveolar fricative within a stem. Alveolar and postalveolar stops, affricates and palatals block coronal harmony, but the flap and non-coronal consonants are reported to be transparent. Kinematic data on consonant production in Kinyarwanda were collected using electromagnetic articulography. The mean angle for the line defined by receivers placed on the tongue tip and blade was calculated over the consonant intervals. Mean angle reliably distinguished alveolar and postalveolar fricatives, with alveolars showing a lower tip relative to blade. Mean angle during transparent non-coronal consonants showed a higher tip relative to blade than in contexts without harmony, and the mean angle during transparent [m] was not significantly different than during postalveolar fricatives. This is consistent with a model where Kinyarwanda coronal harmony extends a continuous tip-blade gesture, causing it to be present during 'transparent' segments, but without perceptible effect.

The Effects of Computer-Assisted Pronunciation Training in the Production of English Coda Consonants and Consonant Clusters

This study is designed to investigate Korean speakers' error patterns in English coda consonant and consonant cluster production, and the effects of a Computer-Assisted Pronunciation Training (CAPT) system. In addition, this study examines the learners' perception of the CAPT program. For these purposes, this study compares the results of the pretest and those of the posttest after a two-week pronunciation training session using Dr. Speaking. A questionnaire is used to gauge participants' reactions to the CAPT system. The results showed that in both the pretest and posttest the majority of errors were made when consonant clusters occurred in the coda position, and vowel insertion errors were predominant. Further, participants showed considerable progress in the pronunciation of English coda consonants and consonant clusters after a short-term training program. The participants' responses to the CAPT system, with respect to the grades and feedback they received, were very positive. These results suggest that a CAPT system providing automatic corrective feedback can be a useful pedagogical tool. However, more individually tailored feedback is needed in place of repetitive and standardized feedback in order to improve the effectiveness of the system.

On The Complementary Nature Of Consonant And Vowel Harmony In Child And Adult Language

There is an intriguing complementary distribution of phonological harmony in child and adult language. Whereas vowel harmony is frequently, and consonant harmony rarely, found in fully-developed phonologies, the opposite is true of developing phonologies. This contrast materializes in the face of a long list of similarities suggesting that harmony in child and adult language is essentially the same process. The following three factors are shown to have a bearing on phonological harmony—ease of articulation, ease of programming and distinctiveness. Ease of programming is claimed to facilitate harmony in general, ease of articulation to favour consonant harmony and distinctiveness to favour vowel harmony. Because the production of consonants requires more highly developed motor skills than that of vowels, children tend to resort to consonant harmony. Because ease of articulation plays a limited role in adult language, the bias introduced by distinctiveness unfolds itself in unrestrained fashion and occasions vowel harmony in adult phonologies.

Production and identification of English word-final nasal consonants by Brazilian EFL learners

This preliminary study aims at investigating the production and perception of the English nasals /m/ and /n/ in word-final position by a group of 10 intermediate Brazilian EFL learners. Production data was collected by means of a Sentence Reading Test considering preceding vowel as phonological context. Perception was assessed by means of an identification test contrasting native-like vs. nonnative-like pronunciation of the target nasal consonants. The results from production suggest that the lack of fully realized word-final nasals in Brazilian Portuguese influenced the Brazilian learners’ production, as they frequently nasalized the preceding vowel and deleted the following nasal consonant. The results from the identification test revealed that it was easier for the participants to identify the native-like realization of English word-final nasals when it was presented in contrast to the nonnative-like realization.

A Neuroimaging Study of Premotor Lateralization and Cerebellar Involvement in the Production of Phonemes and Syllables

This study investigated the network of brain regions involved in overt production of vowels, monosyllables, and bisyllables to test hypotheses derived from the Directions Into Velocities of Articulators (DIVA) model of speech production (Guenther, Ghosh, & Tourville, 2006). The DIVA model predicts left lateralized activity in inferior frontal cortex when producing a single syllable or phoneme and increased cerebellar activity for consonant-vowel syllables compared with steady-state vowels. Sparse sampling functional magnetic resonance imaging (fMRI) was used to collect data from 10 right-handed speakers of American English while producing isolated monosyllables (e.g., "ba," "oo"). Data were analyzed using both voxel-based and participant-specific anatomical region-of-interest-based techniques. Overt production of single monosyllables activated a network of brain regions, including left ventral premotor cortex, left posterior inferior frontal gyrus, bilateral supplementary motor area, sensorimotor cortex, auditory cortex, thalamus, and cerebellum. Paravermal cerebellum showed greater activity for consonant-vowel syllables compared to vowels. The finding of left-lateralized premotor cortex activity supports the DIVA model prediction that this area contains cell populations representing syllable motor programs without regard for semantic content. Furthermore, the superior paravermal cerebellum is more active for consonant-vowel syllables compared with vowels, perhaps due to increased timing constraints for consonant production.