Effects of sampling rate and type of anti-aliasing filter on linear-predictive estimates of formant frequencies in men, women, and children.

The purpose of this study was to assess the effect of downsampling the acoustic signal on the accuracy of linear-predictive (LPC) formant estimation. Based on speech produced by men, women, and children, the first four formant frequencies were estimated at sampling rates of 48, 16, and 10 kHz using different anti-alias filtering. With proper selection of number of LPC coefficients, anti-alias filter and between-frame averaging, results suggest that accuracy is not improved by rates substantially below 48 kHz. Any downsampling should not go below 16 kHz with a filter cut-off centered at 8 kHz.

Corner vowels in males and females ages 4 to 20 years: Fundamental and F1-F4 formant frequencies.

The purpose of this study was to determine the developmental trajectory of the four corner vowels' fundamental frequency (fo) and the first four formant frequencies (F1-F4), and to assess when speaker-sex differences emerge. Five words per vowel, two of which were produced twice, were analyzed for fo and estimates of the first four formants frequencies from 190 (97 female, 93 male) typically developing speakers ages 4-20 years old. Findings revealed developmental trajectories with decreasing values of fo and formant frequencies. Sex differences in fo emerged at age 7. The decrease of fo was larger in males than females with a marked drop during puberty. Sex differences in formant frequencies appeared at the earliest age under study and varied with vowel and formant. Generally, the higher formants (F3-F4) were sensitive to sex differences. Inter- and intra-speaker variability declined with age but had somewhat different patterns, likely reflective of maturing motor control that interacts with the changing anatomy. This study reports a source of developmental normative data on fo and the first four formants in both sexes. The different developmental patterns in the first four formants and vowel-formant interactions in sex differences likely point to anatomic factors, although speech-learning phenomena cannot be discounted.

The Feel of Speech: Multisystem and Polymodal Somatosensation in Speech Production.

PURPOSE: The oral structures such as the tongue and lips have remarkable somatosensory capacities, but understanding the roles of somatosensation in speech production requires a more comprehensive knowledge of somatosensation in the speech production system in its entirety, including the respiratory, laryngeal, and supralaryngeal subsystems. This review was conducted to summarize the system-wide somatosensory information available for speech production. METHOD: The search was conducted with PubMed/Medline and Google Scholar for articles published until November 2023. Numerous search terms were used in conducting the review, which covered the topics of psychophysics, basic and clinical behavioral research, neuroanatomy, and neuroscience. RESULTS AND CONCLUSIONS: The current understanding of speech somatosensation rests primarily on the two pillars of psychophysics and neuroscience. The confluence of polymodal afferent streams supports the development, maintenance, and refinement of speech production. Receptors are both canonical and noncanonical, with the latter occurring especially in the muscles innervated by the facial nerve. Somatosensory representation in the cortex is disproportionately large and provides for sensory interactions. Speech somatosensory function is robust over the lifespan, with possible declines in advanced aging. The understanding of somatosensation in speech disorders is largely disconnected from research and theory on speech production. A speech somatoscape is proposed as the generalized, system-wide sensation of speech production, with implications for speech development, speech motor control, and speech disorders.

Vowel Production in Children and Adults With Down Syndrome: Fundamental and Formant Frequencies of the Corner Vowels.

PURPOSE: Atypical vowel production contributes to reduced speech intelligibility in children and adults with Down syndrome (DS). This study compares the acoustic data of the corner vowels /i/, /u/, /æ/, and /ɑ/ from speakers with DS against typically developing/developed (TD) speakers. METHOD: Measurements of the fundamental frequency (f o) and first four formant frequencies (F1-F4) were obtained from single word recordings containing the target vowels from 81 participants with DS (ages 3-54 years) and 293 TD speakers (ages 4-92 years), all native speakers of English. The data were used to construct developmental trajectories and to determine interspeaker and intraspeaker variability. RESULTS: Trajectories for DS differed from TD based on age and sex, but the groups were similar with the striking change in f o and F1-F4 frequencies around age 10 years. Findings confirm higher f o in DS, and vowel-specific differences between DS and TD in F1 and F2 frequencies, but not F3 and F4. The measure of F2 differences of front-versus-back vowels was more sensitive of compression than reduced vowel space area/centralization across age and sex. Low vowels had more pronounced F2 compression as related to reduced speech intelligibility. Intraspeaker variability was significantly greater for DS than TD for nearly all frequency values across age. DISCUSSION: Vowel production differences between DS and TD are age- and sex-specific, which helps explain contradictory results in previous studies. Increased intraspeaker variability across age in DS confirms the presence of a persisting motor speech disorder. Atypical vowel production in DS is common and related to dysmorphology, delayed development, and disordered motor control.

Developing and validating the Communication Function Classification System for individuals with cerebral palsy.

AIM: The purpose of this study was to create and validate the Communication Function Classification System (CFCS) for children with cerebral palsy (CP), for use by a wide variety of individuals who are interested in CP. This paper reports the content validity, interrater reliability, and test-retest reliability of the CFCS for children with CP. METHOD: An 11-member development team created comprehensive descriptions of the CFCS levels, and four nominal groups comprising 27 participants critiqued these levels. Within a Delphi survey, 112 participants commented on the clarity and usefulness of the CFCS. Interrater reliability was completed by 61 professionals and 68 parents/relatives who classified 69 children with CP aged 2 to 18 years. Test-retest reliability was completed by 48 professionals who allowed at least 2 weeks between classifications. The participants who assessed the CFCS were all relevant stakeholders: adults with CP, parents of children with CP, educators, occupational therapists, physical therapists, physicians, and speech-language pathologists. RESULTS: The interrater reliability of the CFCS was 0.66 between two professionals and 0.49 between a parent and a professional. Professional interrater reliability improved to 0.77 for classification of children older than 4 years. The test-retest reliability was 0.82. INTERPRETATION: The CFCS demonstrates content validity and shows very good test-retest reliability, good professional interrater reliability, and moderate parent-professional interrater reliability. Combining the CFCS with the Gross Motor Function Classification System and the Manual Ability Classification System contributes to a functional performance view of daily life for individuals with CP, in accordance with the World Health Organization's International Classification of Functioning, Disability and Health.

The birth and growth of a scientific journal.

Clinical Linguistics & Phonetics (CLP) and its namesake field have accomplished a great deal in the last quarter of a century. The success of the journal parallels the growth and vitality of the field it represents. The markers of journal achievement are several, including increased number of journal pages published annually; greater diversity of topics related to the core mission of the journal; expanding cross-language coverage; and healthy interactions among editors, reviewers and contributors; and - for better or worse - journal impact factors. A journal is in a competitive dynamic with other journals that share its general domain of scholarship, which is a major reason why an apparent imbalance may emerge in the topic content of any particular journal. The content of a journal is determined by the nature and number of submitted manuscripts. As far as linguistic content goes, CLP's centre of gravity appears to have been mostly in phonology and phonetics, but certainly not to the exclusion of syntax, semantics and pragmatics. The clinical scope is broad, both in terms of concepts and types of disorder. CLP has secured its place among journals in the field, and it is an outlet of choice for many researchers throughout the world.

Acoustic parameters of voice in typically developing children ages 4-19 years.

OBJECTIVES: Report data on acoustic measures of voice in sustained vowels produced by typically developing children, aged 4-19 years, to add to the cross-sectional reference values in a pediatric database. METHODS: Recordings of sustained vowel/ɑ/phonation were obtained from 158 children (80 males, 78 females) aged 4-19 years who were judged to be typically developing with respect to speech and voice. Acoustic analyses were performed with the Multidimensional Voice Program (MDVP™) and the Analysis of Dysphonia in Speech and Voice (ADSV™), both from Pentax Medical. RESULTS: Values from both MDVP and ADSV are reported for children in the following age cohorts: 4-6 years, 7-9 years, 10-12 years, 13-15 years, and 16-19 years. CONCLUSION: The data in this study complement previously published data and contribute to a pediatric reference database useful for research and for clinical practice related to children's voice. Acoustic parameters most sensitive to age and sex are identified.

Auditory-Perceptual Features of Speech in Children and Adults With Down Syndrome: A Speech Profile Analysis.

Purpose The aim of this study was to determine how the speech disorder profiles in Down syndrome (DS) relate to reduced intelligibility, atypical overall quality, and impairments in the subsystems of speech production (phonation, articulation, resonance, and prosody). Method Auditory-perceptual ratings of intelligibility, overall quality, and features associated with the subsystems of speech production were obtained from recordings of 79 children and adults with DS. Ratings were made for sustained vowels (62 of 79 speakers) and short sentences (79 speakers). The data were analyzed to determine the severity of the affected features in each speaking task and to detect patterns in the group data by means of principal components analysis. Results Reduced intelligibility was noted in 90% of the speakers, and atypical overall speech quality was noted in 100%. Affected speech features were distributed across the speech production subsystems. Principal components analysis revealed four components each for the vowel and sentence tasks, showing that individuals with DS are not homogeneous in the features of their speech disorder. Discussion The speech disorder in DS is complex in its perceptual features and reflects impairments across the subsystems of speech production, but the pattern is not uniform across individuals, indicating that attention must be given to individual variation in designing treatments.

Opportunities, barriers, and recommendations in down syndrome research.

BACKGROUND: Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community. OBJECTIVE: The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan. METHODS: NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS. RESULTS: This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade. CONCLUSIONS: This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Effects of a curved vocal tract with grid-generated tongue profile on low-order formants.

A hyperbolic grid-generation algorithm allows investigation of the effect of vocal-tract curvature on low-order formants. A smooth two-dimensional (2D) curve represents the combined lower lip, tongue, and anterior pharyngeal wall profile as displacements from the combined upper lip, palate, and posterior pharyngeal wall outline. The algorithm is able to generate tongue displacements beyond the local radius of strongly curved sections of the palate. The 2D grid, along with transverse profiles of the lip, oral-pharyngeal, and epilarynx regions, specifies a vocal conduit from which an effective area function may be determined using corrections to acoustic parameters resulting from duct curvature; the effective area function in turn determines formant frequencies through an acoustic transmission-line calculation. Results of the corrected transmission line are compared with a three-dimensional finite element model. The observed effects of the curved vocal tract on formants F1 and F2 are in order of importance, as follows: (1) reduction in midline distances owing to curvature of the palate and the bend joining the palate to the pharynx, (2) the curvature correction to areas and section lengths, and (3) adjustments to the palate-tongue distance required to produce smooth tongue shapes at large displacements from the palate.

Segmental production in Mandarin-learning infants.

The early development of vocalic and consonantal production in Mandarin-learning infants was studied at the transition from babbling to producing first words. Spontaneous vocalizations were recorded for 24 infants grouped by age: G1 (0 ; 7 to 1 ; 0) and G2 (1 ; 1 to 1 ; 6). Additionally, the infant-directed speech of 24 caregivers was recorded during natural infant-adult interactions to infer language-specific effects. Data were phonetically transcribed according to broad categories of vowels and consonants. Vocalic development, in comparison with reports for children of other linguistic environments, exhibited two universal patterns: the prominence of [symbol: see text] and [symbol: see text], and the predominance of low and mid vowels over high vowels. Language-specific patterns were also found, e.g. the early appearance and acquisition of low vowels [symbol: see text]. Vowel production was similar in G1 and G2, and a continuum of developmental changes brought infants' vocalization closer to the adult model. Consonantal development showed two universal patterns: labials and alveolars occurred more frequently than velars; and nasals developed earlier than fricatives, affricates and liquids. We also found two language-specific patterns: alveolars were more prominent than labials and affricates developed early. Universal and language-specific characteristics in G1 continued to be prominent in G2. These data indicate that infants are sensitive to the ambient language at an early age, and this sensitivity influences the nature of their vocalizations.

Vowel Acoustics and Speech Intelligibility in Young Adults With Down Syndrome.

Purpose Speech production deficits and reduced intelligibility are frequently noted in individuals with Down syndrome (DS) and are attributed to a combination of several factors. This study reports acoustic data on vowel production in young adults with DS and relates these findings to perceptual analysis of speech intelligibility. Method Participants were eight young adults with DS as well as eight age- and gender-matched typically developing (TD) controls. Several different acoustic measures of vowel centralization and variability were applied to tokens of corner vowels (/ɑ/, /æ/, /i/, /u/) produced in common English words. Intelligibility was assessed for single-word productions of speakers with DS, by means of transcriptions from 14 adult listeners. Results Group differentiation was found for some, but not all, of the acoustic measures. Low vowels were more acoustically centralized and variable in speakers with DS than TD controls. Acoustic findings were associated with overall intelligibility scores. Vowel formant dispersion was the most sensitive measure in distinguishing DS and TD formant data. Conclusion Corner vowels are differentially affected in speakers with DS. The acoustic characterization of vowel production and its association with speech intelligibility scores within the DS group support the conclusion of motor control deficits in the overall speech impairment. Implications are discussed for effective treatment planning.

Oral and manual force control in preschool-aged children: is there evidence for common control?

The authors examined and compared the development of oral and manual force control in preschool-aged children. In all, 50 typically developing children (aged 3-5 years) performed maximal strength tasks and submaximal visually guided tasks using tongue elevation, power, and precision grips. Dependent measures included strength, rate of force rise, initial force overshoot, force variability, and rate of force release. The authors performed age- and performance-related analyses. Results revealed similar changes for tongue, fingers, and hands across age- and performance-related measures for strength, initial force overshoot, and rate of force release. There were no significant changes in rate of force rise with increasing age. Force variability measures showed effector-specific changes with decreases across age- and performance-related measures for the hands and fingers but not for the tongue. Changes common across effector systems likely reflect biological development coupled with cognitive-strategic development. Effector-specific changes in force variability likely reflect experience gained through functional tasks influencing biological and cognitive-strategic development. Lack of change in force variability of the tongue suggests that fine control of the tongue is activity specific; thus, nonfunctional tasks are not likely to be sensitive to experience-related biological development.

Statistical models of F2 slope in relation to severity of dysarthria.

OBJECTIVE: This study investigated the distribution of second-formant (F2) slopes in a relatively large number of speakers with dysarthria associated with two different underlying diseases. PATIENTS AND METHODS: Forty speakers with dysarthria (20 with Parkinson's disease, PD; 20 with stroke) and 5 control speakers without a history of neurological disease were asked to repeat six words (coat, hail, sigh, shoot, row and wax) 10 times. Acoustic analysis was performed to derive F2 slope, and speech intelligibility data were collected using a direct magnitude estimate technique to examine its relationship to F2 slope. RESULTS: Statistical analysis revealed that both clinical groups showed significantly reduced F2 slopes compared to healthy speakers for all words but row. No group difference was found between speakers with PD and stroke; however, different words showed varying sensitivity to the speech motor control problems. The F2 slopes of only two words, shoot and wax, were significantly correlated with scaled speech intelligibility. CONCLUSION: The findings support the idea that distributional characteristics of acoustic variables, such as F2 slope, could be used to develop a quantitative metric of severity of speech motor control deficits in dysarthria, when the materials are appropriately selected and additional distributional characteristics are studied.

Disfluency clusters in speakers with and without neurogenic stuttering following traumatic brain injury.

PURPOSE: Analyze the characteristics and rate of disfluency clusters in adults with and without neurogenic stuttering after traumatic brain injury (TBI). METHOD: Twenty adults with TBI participated in this study, including 10 with neurogenic stuttering (Group B) and 10 without -stuttering (Group A). Disfluency clusters in speech samples were classified into three types: Stuttering-like (SLD), other (OD), and mixed (MIX). RESULTS: Speakers with and without neurogenic stuttering produced the same mean number of disfluency clusters. In addition, the mean length of clusters did not differ between these speaker groups although the longest clusters did. The most frequently occurring cluster type for people with neurogenic stuttering was MIX and OD for people without stuttering. Although the speakers in Group A produced stuttering-like disfluencies, these never occurred together to form a SLD type cluster. For Group B, the starter units of the clusters were usually stuttering-like disfluencies, while for Group A, the starter units were mostly interruptions. CONCLUSIONS: Compared to non-stuttering speakers, stuttering after TBI did not increase the number of clusters, but rather lengthened them. In speakers with neurogenic stuttering, the number and length of clusters were related to the manifestation of other communication deficits, not to the frequency of stuttering-like disfluencies. Still, SLD clusters occurred only in those people with neurogenic stuttering. These findings raise questions about the nature of both neurogenic stuttering and the dynamics of disfluency clustering.

Static measurements of vowel formant frequencies and bandwidths: A review.

PURPOSE: Data on vowel formants have been derived primarily from static measures representing an assumed steady state. This review summarizes data on formant frequencies and bandwidths for American English and also addresses (a) sources of variability (focusing on speech sample and time sampling point), and (b) methods of data reduction such as vowel area and dispersion. METHOD: Searches were conducted with CINAHL, Google Scholar, MEDLINE/PubMed, SCOPUS, and other online sources including legacy articles and references. The primary search items were vowels, vowel space area, vowel dispersion, formants, formant frequency, and formant bandwidth. RESULTS: Data on formant frequencies and bandwidths are available for both sexes over the lifespan, but considerable variability in results across studies affects even features of the basic vowel quadrilateral. Origins of variability likely include differences in speech sample and time sampling point. The data reveal the emergence of sex differences by 4 years of age, maturational reductions in formant bandwidth, and decreased formant frequencies with advancing age in some persons. It appears that a combination of methods of data reduction provide for optimal data interpretation. CONCLUSION: The lifespan database on vowel formants shows considerable variability within specific age-sex groups, pointing to the need for standardized procedures.

Effects of Aging on Vocal Fundamental Frequency and Vowel Formants in Men and Women.

PURPOSE: This study reports data on vocal fundamental frequency (fo) and the first four formant frequencies (F1, F2, F3, F4) for four vowels produced by speakers in three adult age cohorts, in a test of the null hypothesis that there are no age-related changes in these variables. Participants were 43 men and 53 women between the ages of 20 and 92 years. RESULTS: The most consistent age-related effect was a decrease in fo for women. Significant differences in F1, F2, and F3 were vowel-specific for both sexes. No significant differences were observed for the highest formant F4. CONCLUSIONS: Women experience a significant decrease in fo, which is likely related to menopause. Formant frequencies of the corner vowels change little across several decades of adult life, either because physiological aging has small effects on these variables or because individuals compensate for age-related changes in anatomy and physiology.

Listener agreement for auditory-perceptual ratings of dysarthria.

PURPOSE: Darley, Aronson, and Brown (1969a, 1969b) detailed methods and results of auditory-perceptual assessment for speakers with dysarthrias of varying etiology. They reported adequate listener reliability for use of the rating system as a tool for differential diagnosis, but several more recent studies have raised concerns about listener reliability using this approach. METHOD: In the present study, the authors examined intrarater and interrater agreement for perceptual ratings of 47 speakers with various dysarthria types by 2 listener groups (inexperienced and experienced). The entire set of perceptual features proposed by Darley et al. was rated based on a 40-s conversational speech sample. RESULTS: No differences in levels of agreement were found between the listener groups. Agreement was within 1 scale value or better for 67% of the pairwise comparisons. Levels of agreement were lower when the average rating fell in the mid-range of the scale compared with samples that had an average rating near either of the scale endpoints; agreement was above chance level. No significant differences in agreement were found between the perceptual features. DISCUSSION: The levels of listener agreement that were found indicate that auditory-perceptual ratings show promise during clinical assessment for identifying salient features of dysarthria for speakers with various etiologies.

The effect of botulinum toxin A (Botox) injections used to treat limb spasticity on speech patterns in children with dysarthria and cerebral palsy: A report of two cases.

Botulinum toxin A (Btx-A) injections are used to treat limb spasticity in children with cerebral palsy (CP) resulting in improved gross and fine motor control. This treatment has also been reported to have additional functional effects, but the effect of treatment on speech has not been reported. This report presents results of longitudinal speech evaluation of two children with CP given injections of Btx-A for treatment of limb spasticity. Speech evaluations were accomplished at baseline (date of injections) and 4- and 10-weeks post-injections. Improvements in production of consonants, loudness control, and syllables produced per breath were found. Parental survey also suggested improvements in subjects' speech production and willingness to speak outside the testing situation. Future larger studies are warranted to assess the nature of the changes observed related to Btx-A.