An acoustic-articulatory description of children's defective /s/ productions

Development and Resolution of Nasal Fricatives in a Child with Repaired Bilateral Cleft Lip and Palate: A Case Report

PURPOSE

This case report describes the development, characteristics, and resolution of anterior nasal fricatives (ANFs) - a learned maladaptive articulation error - in a young girl with repaired bilateral cleft lip and palate.

METHOD

The girl was observed every two months from 12 to 24 months of age with follow-ups at 36, 48, and 67 months of age.

RESULTS

At 12 months of age, the girl nasalized /b/ inconsistently and had mild conductive hearing loss. At 18 months of age, she exhibited audible nasal air emission on some plosives and used ANFs to replace /s/ and /z/, often with a nasal grimace. At 24 months of age, the child continued to experience mild conductive hearing loss, obligatory nasal air emission, and ANFs for /s/ and /z/. At 36 months of age, pressure-flow testing documented significant velopharyngeal (VP) dysfunction. The girl then used ANFs for /f/ and /s/, phonetically marked by different oral stops. At 48 months of age, although VP impairment continued, speech therapy largely eliminated ANFs. By 67 months of age, VP closure was nearly normal.

CONCLUSIONS

Multiple factors including VP dysfunction, audible nasal air emission, and conductive hearing loss contributed to the development of ANFs. Clinical and etiological implications are discussed.

Obligatory Nasal Turbulence as a Trigger for the Development of Posterior Nasal Fricatives in a Child With Repaired Cleft Palate

Posterior nasal fricatives (PNFs) are unusual articulations that occur in some children with and without cleft palate. The etiology of PNFs is unclear. A young girl with repaired cleft palate is described who exhibited inconsistent obligatory nasal turbulence during production of stops at 2 years of age. At 3 years of age, she exhibited various phonological processes and used PNFs to replace sibilants and affricates. Pressure-flow testing showed a relatively small velopharyngeal area during production of stops. These observations are consistent with obligatory nasal turbulence triggering the development of PNFs as an unusual phonological process, perhaps facilitated by reduced hearing.

Sibilant production in Hebrew-speaking adults: Apical versus laminal

The Hebrew IPA charts describe the sibilants /s, z/ as 'alveolar fricatives', where the place of articulation on the palate is the alveolar ridge. The point of constriction on the tongue is not defined - apical (tip) or laminal (blade). Usually, speech and language pathologists (SLPs) use the apical placement in Hebrew articulation therapy. Some researchers and SLPs suggested that acceptable /s, z/ could be also produced with the laminal placement (i.e. the tip of the tongue approximating the lower incisors). The present study focused at the clinical level, attempting to determine the prevalence of these alternative points of constriction on the tongue for /s/ and /z/ in three different samples of Hebrew-speaking young adults (total n = 242), with typical articulation. Around 60% of the participants reported using the laminal position, regardless of several speaker-related variables (e.g. tongue-thrust swallowing, gender). Laminal production was more common in /s/ (than /z/), coda (than onset) position of the sibilant, mono- (than di-) syllabic words, and with non-alveolar (than alveolar) adjacent consonants. Experiment 3 revealed no acoustical differences between apical and laminal productions of /s/ and of /z/. From a clinical perspective, we wish to raise the awareness of SLPs to the prevalence of the two placements when treating Hebrew speakers, noting that tongue placements were highly correlated across sibilants. Finally, we recommend adopting a client-centred practice, where tongue placement is matched to the client. We further recommend selecting targets for intervention based on our findings, and separating between different prosodic positions in treatment.

Does the recording medium influence phonetic transcription of cleft palate speech?

BACKGROUND

In recent years, analyses of cleft palate speech based on phonetic transcriptions have become common. However, the results vary considerably among different studies. It cannot be excluded that differences in assessment methodology, including the recording medium, influence the results.

AIMS

To compare phonetic transcriptions from audio and audio/video recordings of cleft palate speech by means of outcomes of per cent correct consonants (PCC) and differences in consonant transcriptions.

METHODS & PROCEDURES

Thirty-two 3-year-olds born with cleft palate were audio and audio/video recorded while performing a single-word test by picture naming. The recordings were transcribed according to the International Phonetic Alphabet. The transcriptions from the audio and the audio/video recordings were analysed with regard to PCC, differences in the use of phonetic consonant symbols and the use of diacritics.

OUTCOMES & RESULTS

PCC was higher when the calculation was based on transcriptions from audio recordings than when based on audio/video recordings. No such differences were seen when age-appropriate consonant processes were scored as correct. Consonants were not excluded as often in the transcriptions from audio/video recordings as they were in the transcriptions from audio recordings, and more target consonants were transcribed as dental/alveolar in the transcriptions from audio/video recordings and palatal/velar/uvular in the transcriptions from audio recordings than vice versa. Further, interdental articulation, linguolabial articulation and audible nasal air leakage were more common in the transcriptions from audio/video recordings than in those from audio recordings. All these differences were statistically significant.

CONCLUSIONS & IMPLICATIONS

Phonetic transcription is influenced to some extent by visual cues. However, as long as age-appropriate articulatory and phonological simplification processes are scored as correct when evaluating consonant production in the speech of young children born with cleft palate using phonetic transcription, the recording medium does not seem to affect the results.

Fricative Contrast and Coarticulation in Children With and Without Speech Sound Disorders

PURPOSE

The purpose of this study was, first, to expand our understanding of typical speech development regarding segmental contrast and anticipatory coarticulation, and second, to explore the potential diagnostic utility of acoustic measures of fricative contrast and anticipatory coarticulation in children with speech sound disorders (SSD).

METHOD

In a cross-sectional design, 10 adults, 17 typically developing children, and 11 children with SSD repeated carrier phrases with novel words with fricatives (/s/, /ʃ/). Dependent measures were 2 ratios derived from spectral mean, obtained from perceptually accurate tokens. Group analyses compared adults and typically developing children; individual children with SSD were compared to their respective typically developing peers.

RESULTS

Typically developing children demonstrated smaller fricative acoustic contrast than adults but similar coarticulatory patterns. Three children with SSD showed smaller fricative acoustic contrast than their typically developing peers, and 2 children showed abnormal coarticulation. The 2 children with abnormal coarticulation both had a clinical diagnosis of childhood apraxia of speech; no clear pattern was evident regarding SSD subtype for smaller fricative contrast.

CONCLUSIONS

Children have not reached adult-like speech motor control for fricative production by age 10 even when fricatives are perceptually accurate. Present findings also suggest that abnormal coarticulation but not reduced fricative contrast is SSD-subtype-specific.

SUPPLEMENTAL MATERIALS

S1: https://doi.org/10.23641/asha.5103070. S2 and S3: https://doi.org/10.23641/asha.5106508.

SVANTE - The Swedish Articulation and Nasality Test - Normative data and a minimum standard set for cross-linguistic comparison

Normative language-based data are important for comparing speech performances of clinical groups. The Swedish Articulation and Nasality Test (SVANTE) was developed to enable a detailed speech assessment. This study's aim was to present normative data on articulation and nasality in Swedish speakers. Single word production, sentence repetition and connected speech were collected using SVANTE in 443 individuals. Mean (SD) and prevalences in the groups of 3-, 5-, 7-, 10-, 16- and 19-year-olds were calculated from phonetic transcriptions or ordinal rating. For the 3- and 5-year-olds, a consonant inventory was also determined. The mean percent of oral consonants correct ranged from 77% at age 3 to 99% at age 19. At age 5, a mean of 96% was already reached, and the consonant inventory was established except for /s/, /r/, /ɕ/. The norms on the SVANTE, also including a short version, will be useful in the interpretation of speech outcomes.

Electropalatographic (EPG) evidence of covert contrasts in disordered speech

The phenomenon of covert contrasts has intrigued researchers and clinicians since it was first identified using instrumental data nearly 50 years ago. The term covert contrast refers to phonological contrasts that listeners do not readily identify and which therefore pass unrecorded in transcription-based studies. Covert contrasts are viewed as significant from theoretical and clinical perspectives. Although influential, there are relatively few instrumental studies of covert contrasts. The studies that do exist are limited to revealing contrasts that manifest in specific phonetic parameters or phonological processes. However, recent studies have provided convincing new evidence that covert contrasts are likely to be widespread in child speech. The purpose of this article is threefold: to review electropalatography (EPG) studies of covert contrasts; to provide EPG examples from the speech of individuals with speech disorders and to discuss the implications in child speech.

Toward improved spectral measures of /s/: results from adolescents

PURPOSE

This article introduces theoretically driven acoustic measures of /s/ that reflect aerodynamic and articulatory conditions. The measures were evaluated by assessing whether they revealed expected changes over time and labiality effects, along with possible gender differences suggested by past work.

METHOD

Productions of /s/ were extracted from various speaking tasks from typically speaking adolescents (6 boys, 6 girls). Measures were made of relative spectral energies in low- (550-3000 Hz), mid- (3000-7000 Hz), and high-frequency regions (7000-11025 Hz); the mid-frequency amplitude peak; and temporal changes in these parameters. Spectral moments were also obtained to permit comparison with existing work.

RESULTS

Spectral balance measures in low-mid and mid-high frequency bands varied over the time course of /s/, capturing the development of sibilance at mid-fricative along with showing some effects of gender and labiality. The mid-frequency spectral peak was significantly higher in nonlabial contexts, and in girls. Temporal variation in the mid-frequency peak differentiated ±labial contexts while normalizing over gender.

CONCLUSIONS

The measures showed expected patterns, supporting their validity. Comparison of these data with studies of adults suggests some developmental patterns that call for further study. The measures may also serve to differentiate some cases of typical and misarticulated /s/.

Influence of adenotonsillar hypertrophy on /s/-articulation in children--effects of surgery

Tonsillar hypertrophy is common in young children and affects several aspects of the speech such as distortions of the dento-alveolar consonants. The study objective was to assess /s/-articulation, perceptually and acoustically, in children with tonsillar hypertrophy and compare effects of two types of surgery, total tonsillectomy and tonsillotomy. Sixty-seven children, aged 50-65 months, on the waiting list for surgery, were randomized to tonsillectomy or tonsillotomy. The speech material was collected preoperatively and 6 months postoperatively. Two groups of age-matched children were controls. /S/-articulation was affected acoustically with lower spectral peak locations and perceptually with less distinct /s/-production before surgery, in comparison to controls. After surgery /s/-articulation was normalized perceptually, but acoustic differences remained. No significant differences between surgical methods were found.

Speech performance in lingual orthodontic patients measured by sonagraphy and auditive analysis

Esthetically appealing, externally invisible, lingually applied orthodontic brackets are in increasing demand. Because the brackets are placed lingually, however, they appear to cause some problems with respect to speech. This study is the first to present a prospective evaluation of the articulation of 23 patients with lingual brackets by means of an innovative combination of test methods. An acoustic, objective evaluation of articulation measured by digital sonagraphy was related to a semiobjective auditive evaluation by 10 speech professionals, to a semiobjective auditive evaluation by close contacts of the patients, and to a subjective auditive evaluation by the patients themselves, the latter 2 using standardized questionnaires. The tests were performed before (T1), within 24 hours after (T2), and 3 months (+/- 1 week) after (T3) the start of therapy. In comparison with the initial findings, a significant deterioration in articulation was recorded with all test methods at T2 and T3. Using a new combination of methods, our investigations show the need for detailed briefing of patients about the extent and duration of changes in speech resulting from lingual brackets.

Acoustic and perceptual analysis of the sibilant sound /s/ before and after orthognathic surgery

PURPOSE

Orthognathic surgery may have a positive or negative effect on speech. Perceptual evaluation of presurgical and postsurgical articulation is difficult because speech errors, when they occur, are usually fricative distortions, which may be difficult to document reliably. In this study, acoustic analysis was used to supplement perceptual judgment of presurgical and postsurgical productions of /s/.

SUBJECTS AND METHODS

The study population consisted of 9 Cantonese speakers undergoing osteotomy for Class III skeletal deformity and 9 age- and gender-matched adults with normal occlusion and speech. The speech sample consisted of 6 words with the initial sibilant sound /s/. Perceptual analysis included narrow phonetic transcription and classification of error types. Acoustic analysis included measurement of first and second spectral peaks, fricative duration, noise bandwidth, and noise-to-vowel decibel ratio.

RESULTS

The results of the perceptual analysis showed a decrease in articulatory errors for the group after surgery, although 5 patients had no perceptual errors before surgery. Acoustic analysis showed significant differences between the experimental and control groups before surgery for 2 variables (spectral peak I and bandwidth). Three months after surgery there were no significant differences between the control group and the experimental group, except for bandwidth. Twelve months after surgery, there were significant differences between the 2 groups in noise bandwidth and spectral peak II.

CONCLUSIONS

The results suggest a possible relapse at 1 year after surgery, based on spectral peak values. Osteotomy appears to result in a positive change in articulation for most patients, but speech outcome after osteotomy must be evaluated both 1 year and shortly after surgery.

An acoustical study of the fricative /s/ in the speech of individuals with dysarthria

This paper reports on measurements of several acoustic attributes of the fricative consonant /s/ produced in word-initial position by normally speaking adults and by speakers with neuromotor dysfunctions. Several acoustic properties are evaluated: the spectrum shape of the fricative and its amplitude in relation to the following vowel, the presence or absence of voicing, the time variation of the spectrum during the fricative and in the transition to the following vowel, and the presence of inappropriate acoustic patterns preceding the /s/. Some of these properties are based on quantitative measurements of the spectrum of the /s/, and others are based on observations of the time-varying acoustic patterns in spectrograms. For the individuals with dysarthria, deviations of each of these properties from the normal range are interpreted in terms of specific deficits in the control of the speech-production system. For the most part, these parameters are highly correlated with the speakers' overall intelligibility, with the intelligibility of words containing the fricative /s/, and with perceptual ratings of the adequacy of the fricative production. The parameters that show the best correlation with intelligibility and perceptual ratings are (a) measures of deviations from normalcy in the time variation of the acoustic pattern within the consonant and at the consonant-vowel boundary and (b) the spectrum shape of the frication noise. These acoustic parameters are related to deviations in the temporal pattern of control of the articulators in producing fricative-vowel sequences and to lack of fine control of the tongue blade in achieving an appropriate target configuration for the fricative.

Perception of lateral misarticulation and its physical correlates

In order to clarify the relationship between perceptual diagnosis of lateral misarticulation (LM) by sophisticated listeners and the physical correlates of LM, three experiments using sustained speech /integral/ were conducted. Experiment 1 was designed to compare the spectral envelopes of normal speech (NS) /integral/ with those of LM /integral/. Experiment 2 was designed to collect the auditory impressions of sophisticated listeners listening to LM and NS /integral/ with specific spectral envelope bands replaced by LM. These two experiments showed that: (1) the spectral envelopes of LM are flat or decrease along the frequency axis in the frequency band above approximately 4 kHz, and there is a substantial peak at around 3.2 kHz in LM, which varies peculiarly with time; (2) the replacement of the spectral envelope between 2.5 and 4.5 kHz of NS with that of LM resulted in a remarkable increase in auditory impressions of LM. The facts suggest that the spectral envelope characteristic of LM has a peculiar variation at around 3.2 kHz. Additionally, experiment 3 estimated the spectrum of sustained speech /integral/ using vocal tract area functions. The results suggest that typical peaks of LM are related to the length and position of the vocal tract constriction region.

Acoustic characteristics of /s/ in adolescents

The goal of the current study was to construct a reference database against which misarticulations of /s/ can be compared. Acoustic data for 26 typically speaking 9- to 15-year-olds were examined to resolve measurement issues in acoustic analyses, including alternative sampling points within the /s/ frication; the informativeness of linear versus Bark transformations of each of the 4 spectral moments of /s/ (Forrest, Weismer, Milenkovic, & Dougall, 1988); and measurement effects associated with linguistic context, age, and sex. Analysis of the reference data set indicates that acoustic characterization of /s/ is appropriately and optimally (a) obtained from the midpoint of /s/, (b) represented in linear scale, (c) reflected in summary statistics for the 1 st and 3rd spectral moments, (d) referenced to individual linguistic-phonetic contexts, (e) collapsed across the age range studied, and (f) described individually by sex.

The substitution of [s] for aspirated targets: perceptual and acoustic evidence from Cantonese

The substitution of [s] for word-initial aspirated targets was examined in a Cantonese-speaking pre-school child. Perceptual analysis showed that the child produced [ph] accurately, but substituted [s] for /t(h)/, /ts(h)/ and /k(h)/. Acoustic analysis revealed no subphonemic contrast between the target /s/, and the substituted [s] for /t(h)/, /ts(h)/ and /k(h)/. The unusual substitution of [s] for aspirated lingual targets, and the lack of a subphonemic contrast among [s] productions were described in terms of feature geometry. The target feature patterns of [-continuant, +spread] were produced as [+continuant, +spread], with maintenance of the default place feature (coronal). It is proposed that the child had immature motor control of the coordination of supralaryngeal and laryngeal movements. Examination of the child's productions of aspirated lingual targets at pre-, mid- and post-therapy revealed that compensatory articulation changed over time as the child learned to coordinate laryngeal and oral movements.

Perceptual characteristics of consonant errors associated with malocclusion

The characteristics of articulation errors made by subjects having a class II, class II with open-bite, class III, or class III with open-bite malocclusion were compared. Regardless of the type of occlusal defect, errors occurred primarily on the sibilants /s, z/ and "sh, ch, j, dz," which were characterized mostly by combined visual and auditory distortions. Errors on the stop consonants /p, b, m, t, d, n/ occurred less frequently and, in all cases, consisted of isolated visual distortions. The type of malocclusion had a specific influence on the nature of the sound error. Subjects having a class II malocclusion, with or without an open bite, were able to assume a variety of tongue and mandibular postures that allowed them to approximate an /s/ or /z/. These compensations did not occur in subjects with a class III malocclusion. In these cases, the tongue remained distal to the mandibular incisors, causing the air stream to scatter. This study suggests that certain groups of sounds were more susceptible to specific types of misproductions and to particular types of occlusal defects.

Electropalatographic investigation of abnormal lingual-palatal contact patterns in cleft palate patients

Lingual-palatal contact patterns and auditorily judged misarticulations, classed as palatalized misarticulation (PM), lateral misarticulation (LM), nasopharyngeal misarticulation (NM), and other distortions were compared in 53 Japanese cleft palate patients. Velopharyngeal function of these patients was considered within normal limits. Contact patterns were recorded by electropalatography (EPG) in an attempt to objectively categorize the misarticulations of cleft palate speakers including those previously reported in English. It is concluded that these lingual-palatal contact patterns are characterized by a broader and/or more posterior pattern than found in normal speakers, although considerable variability was noted.

Anticipatory coarticulation in the speech of adults and young children: acoustic, perceptual, and video data

Three experiments investigated anticipatory lingual and labial coarticulation in the [sV] productions of children and adults. Acoustic, perceptual, and video data were used to trace the development of intrasyllabic coarticulation in the speech of adults and children (ages 3, 5, and 8 years). Although children show greater variability in their articulatory patterns than adults, the data do not support claims that young children produce a greater degree of intrasyllabic coarticulation than older children or adults. Rather, the acoustic and video data suggest that young children and adults produce similar patterns of anticipatory coarticulation, and the perceptual data indicate that coarticulatory cues in the speech of 3-year-old children are less perceptible than those of the other age groups.

Misarticulation caused by abnormal lingual-palatal contact in patients with cleft palate with adequate velopharyngeal function

Misarticulations produced by three patients with cleft palate (2 isolated cleft palate; 1 unilateral cleft lip, alveolus, and palate) who attained adequate velopharyngeal function and normal palatal vault by early surgical repairs were examined using electropalatography (EPG) and sound spectrography (SG). Common characteristics of lingual-palatal contact in which the contact area was broader and/or was more posterior than normal were observed. These misarticulations can be divided into three types based on the direction of the breath emission: palatalized misarticulation (in which air passes along the midline of the palate), lateral misarticulation (in which air flows laterally through the occluded dental arch), and nasopharyngeal misarticulation (in which air flows out the nose). These three are considered to be similar to intractable posterior pattern of articulation in cleft palate patients previously reported. However, these types of misarticulations can be produced by cleft patients who have achieved adequate velopharyngeal function and normal palatal vault.

Children's identification of their own /s/ misarticulations

Six /s/ misarticulating children, two normal-articulating children, and four adults identified a variety of /s/ productions as normal and defective. The /s/ samples were embedded in short segments of speech spliced from the sentence repetitions of the same eight children. Results indicate that each misarticulator could identify at least some of his or her own productions as defective. Although no statistically significant differences appeared between groups, the two lateralizing subjects exhibited poorer identification scores on defective /s/ items than did the other groups, possibly indicating somewhat poorer auditory monitoring abilities. Included is a discussion of procedural considerations important to research of this type.