The relation of nasality and nasalance to nasal port area based on a computational model

Gestural Timing Patterns of Nasality in Highly Proficient Spanish Learners of English: Aerodynamic Evidence

Segment-to-segment timing overlap between Vowel-Nasal gestures in /VN/ sequences varies cross-linguistically. However, how bilinguals may adjust those timing gestures is still unanswered. Regarding timing strategies in a second language (L2), research finds that native (L1) strategies can be partially transferred to the L2, and that higher L2 proficiency promotes a more successful phonetic performance. My goal is to answer whether bilingual speakers can adjust their L1 coarticulatory settings in their L2 and to observe whether their L2 accentedness plays a role in ultimate attainment. Ten native speakers of Spanish (L1Sp) who were highly proficient L2 English speakers participated in Spanish and English read-aloud tasks. A control group of 16 L1 English speakers undertook the English experiment. Aerodynamic data were collected using pressure transducers. Each participant produced tokens with nasalized vowels in CVN# words and oral vowels in CV(CV) words. Four linguistically trained judges (two per target language) evaluated a set of pseudo-randomized sentences produced by the participants containing words with nasalized vowels and rated the speech on a 1 (heavily accented) to 9 (native-like) Likert-type scale. Measurements for onset and degree of overall nasality were obtained. Results indicate the L1Sp group can accommodate gestural timing strategies cross-linguistically as they exhibit an earlier nasality onset and increment nasality proportion in L2 English in a native-like manner. In addition, a positive correlation between greater vowel nasality degree and native-like accentedness in the L2 was found, suggesting L2 timing settings might be specified in higher spoken proficiency levels.

The relation of velopharyngeal coupling area and vocal tract scaling to identification of stop-nasal cognates

The purpose of this study was to determine whether the threshold of velopharyngeal (VP) coupling area at which listeners switch from identifying a consonant as a stop to a nasal in North American English was different for speech produced by a model based on an adult male, an adult female, and a 4-year-old child. V1CV2 stimuli were generated with a speech production model that encodes phonetic segments as relative acoustic targets imposed on an underlying vocal tract and laryngeal structure that can be scaled according to sex and age. Each V1CV2 was synthesized with a set of VP coupling functions whose maximum area ranged from 0 to 0.1 cm2. Results showed that scaling the vocal tract and vocal folds had essentially no effect on the VP coupling area at which listener identification shifted from stop to nasal. The range of coupling areas at which the crossover occurred was 0.037-0.049 cm2 for the male model, 0.040-0.055 cm2 for the female model, and 0.039-0.052 cm2 for the 4-year-old child model, and overall mean was 0.044 cm2. Calculations of band limited peak nasalance indicated that 85% peak nasalance during the consonant was well aligned with listener responses.

Treatment Outcomes of Interdisciplinary Care on Speech and Health-Related Quality of Life Outcomes in Adults With Cleft Palate

PURPOSE

Individuals born with a cleft palate with or without a cleft lip (CP ± L) often experience functional, aesthetic, and psychosocial consequences well into adulthood. This study aimed to investigate outcomes of speech and health-related quality of life (HRQoL) in adults with a CP ± L who received interdisciplinary cleft care at the Ghent University Hospital using valid, reliable, and condition-specific instruments.

METHOD

Thirteen Belgian Dutch-speaking participants with a CP ± L with a mean age of 25.4 years (SD = 5.1, range: 20-33 years) and an age- and gender-matched control group of 13 participants without a CP ± L with a mean age of 25.2 years (SD = 4.8, range: 20-32 years) were included in this study. Speech characteristics were evaluated perceptually and instrumentally. HRQoL was assessed through standardized patient-reported outcome measures. Outcomes were compared with those of the control group and to normative data where available.

RESULTS

Participants with a CP ± L in this sample demonstrated significantly lower speech acceptability (p < .001) and higher rates of hypernasality (p = .015) and nasal turbulence (p = .005) than the control group. They showed significantly higher satisfaction with appearance of the cleft scar compared with norms of adults with a CP ± L (p = .047). No other differences in speech characteristics, sociodemographics, or HRQoL were found between participants with and without a CP ± L.

CONCLUSIONS

The reduced speech acceptability and the presence of resonance and nasal airflow disorders may indicate the need for standardized long-term outcome measurement and interdisciplinary follow-up for speech characteristics and velopharyngeal insufficiency in young and middle adulthood in future clinical practice. Additional research is necessary to further substantiate these findings and to determine predictors for these continuing complications in adults with a CP ± L.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24243901.

Numerical investigation of effects of tongue articulation and velopharyngeal closure on the production of sibilant [s]

A numerical simulation of sibilant /s/ production with the realistically moving vocal tract was conducted to investigate the flow and acoustic characteristics during the articulation process of velopharyngeal closure and tongue movement. The articulation process was simulated from the end of /u/ to the middle of /s/ in the Japanese word /usui/, including the tongue elevation and the velopharyngeal valve closure. The time-dependent vocal tract geometry was reconstructed from the computed tomography scan. The moving immersed boundary method with the hierarchical structure grid was adopted to approach the complex geometry of the human speech organs. The acoustic characteristics during the co-articulation process were observed and consistent with the acoustic measurement for the subject of the scan. The further simulations with the different closing speeds of the velopharyngeal closure showed that the far-field sound during the co-articulation process was amplified with the slower closing case, and the velum closure speed was inverse proportional to the sound amplitude with the slope value of − 35.3 dB s/m. This indicates possible phonation of indistinguishable aeroacoustics sound between /u/ and /s/ with slower velopharyngeal closure.

Temporal and Permanent Changes Induced by Maxillary Sinus Lifting with Bone Grafts and Maxillary Functional Endoscopic Sinus Surgery in the Voice Characteristics—Systematic Review

Sinus surgery procedures such as sinus lifting with bone grafting or maxillary functional endoscopy surgery (FESS) can present different complications. The aims of this systematic review are to compile the post-operatory complications of sinus elevation with bone grafting and FESS including voice changes, and to elucidate if those changes are either permanent or temporary. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were used, and the literature was exhaustively searched without time restrictions for randomized and non-randomized clinical studies, cohort studies (prospective and retrospective), and clinical case reports with ≥4 cases focused on sinus lift procedures with bone grafts and functional endoscopic maxillary sinus surgery. A total of 435 manuscripts were identified. After reading the abstracts, 101 articles were selected to be read in full. Twenty articles that fulfilled the inclusion criteria were included for analysis. Within the limitations of this systematic review, complications are frequent after sinus lifting with bone grafts and after FEES. Voice parameters are scarcely evaluated after sinus lifting with bone grafts and no voice changes are reported. The voice changes that occur after FESS include a decreased fundamental frequency, increased nasality, and nasalance, all of which are transitory.

The relation of velopharyngeal coupling area to the identification of stop versus nasal consonants in North American English based on speech generated by acoustically driven vocal tract modulations

The purpose of this study was to determine the threshold of velopharyngeal coupling area at which listeners switch from identifying a consonant as a stop to a nasal in North American English, based on V₁CV₂ stimuli generated with a speech production model that encodes phonetic segments as relative acoustic targets. Each V₁CV₂ was synthesized with a set of velopharyngeal coupling functions whose area ranged from 0 to 0.1 cm². Results show that consonants were identified by listeners as a stop when the coupling area was less than 0.035-0.057 cm², depending on place of articulation and final vowel. The smallest coupling area (0.035 cm²) at which the stop-to-nasal switch occurred was found for an alveolar consonant in the /ɑCi/ context, whereas the largest (0.057 cm²) was for a bilabial in /ɑCɑ/. For each stimulus, the balance of oral versus nasal acoustic energy was characterized by the peak nasalance during the consonant. Stimuli with peak nasalance below 40% were mostly identified by listeners as stops, whereas those above 40% were identified as nasals. This study was intended to be a precursor to further investigations using the same model but scaled to represent the developing speech production system of male and female talkers.

Finite element modeling of the effects of velopharyngeal opening on vocal tract reactance in female voice

Classical singers use nasal consonants as "resonance exercises," and experimental results have shown that singers may use some velopharyngeal opening (VPO), most often in [a:] and more seldom in [i:] or [u:]. In particular, male singers have been found to increase VPO as pitch rises toward register change frequencies (passaggi). Laryngoscopic findings have shown that some VPO stabilizes vocal fold vibration; the effect is related to positive reactance. This study investigates the effects of VPO on vocal tract (VT) reactance over the range of fundamental frequencies (f₀) used in singing using a computerized tomography-based finite element model of the VT and nose of a female. According to the results, by raising the lowest VT resonances, the VPO increased the VT reactance in the frequency ranges 207-359 Hz for [i:], 265-411 Hz for [u:], and 500-611 Hz for [a:], depending on the VPO size (full or half VPO). These frequency ranges are close to the first and second passaggio of a female singer. The change may have an especially practical stabilizing effect for [a:], which is otherwise characterized by very large changes in VT reactance and negative reactance at the second passaggio.

Normative Nasalance Values in Vietnamese With Southern Dialect: Vowel and Tone Effects

Purpose The purpose of the current study was to examine normative nasalance values in Vietnamese adult speakers with Southern dialect and to investigate the effects of vowels and tones on nasalance. Previous studies examining nasalance have been mainly conducted with Indo-European languages. Limited information on nasalance is available in tone languages other than Chinese. Furthermore, tone and vowel effects on nasalance scores in tone languages have not been fully examined. Method Nasalance scores of various speech stimuli including passages, syllables, and prolonged vowels were obtained from Vietnamese-speaking adults with Southern dialect (M _age = 23 years) using a nasometer (KayPENTAX 6450). Results The average nasalance scores of Southern Vietnamese adult speakers were 24.16%, 38.17%, and 70.03% for the oral, oral-nasal, and nasal passages, respectively. Southern Vietnamese speakers produced the highest nasalance scores on the vowel /a/, followed by /i/ and /u/. Nasalance scores of stimuli produced with the falling and restricted tone were significantly lower than those produced with the other tones. Conclusions The normative nasalance values of the current study will contribute as a reference index for the Vietnamese language. The effects of vowels and tones can also provide insight into the development of nasalance testing stimuli and for characterizing nasalance values across languages.

Change in aeroacoustic sound mechanism during sibilant sound with different velopharyngeal opening sizes

The velopharyngeal valve regulates the opening between the nasal and oral cavities. The lack of complete closure is especially problematic in speech because inappropriate leakage of airflow and/or sound into the nasal cavity causes abnormal sound production and increased nasality. The purpose of this study is to use the large eddy simulation approach to examine changes in sound source mechanisms as the size of the opening changes during the production of a sibilant sound. The baseline geometry of the model is based on the pharyngeal airway of a subject having a small velopharyngeal opening while sustaining a sibilant sound. Modifications to the model are done by systematically widening or narrowing the opening (all else being equal). Results show that acoustic energy in the nasal cavity is directly related to the size of the velopharyngeal opening and that there is a critical size where the magnitude of Lighthill's acoustics source in the nasal cavity is maximized. The far-field acoustic energy and its correlation with the sound source mechanisms are also dependent on the size of the velopharyngeal opening. Patient-specific geometry with a velopharyngeal opening during a normal sibilant /s/ sound is shown to the left. Lighthill's acoustic source term is displayed on the right and varies depending on the size of the velopharyngeal opening.

Effects of Nasalization on Vocal Tract Response Curve

BACKGROUND

Earlier studies have shown that nasalization affects the radiated spectrum by modifying the vocal tract transfer function in a complex manner.

METHODS

Here we study this phenomenon by measuring sine-sweep response of 3-D models of the vowels /u, a, ᴂ, i/, derived from volumetric MR imaging, coupled by means of tubes of different lengths and diameters to a 3-D model of a nasal tract.

RESULTS

The coupling introduced a dip into the vocal tract transfer function. The dip frequency was close to the main resonance of the nasal tract, a result in agreement with the Fujimura & Lindqvist in vivo sweep tone measurements [Fujimura & Lindqvist, 1972]. With increasing size of the coupling tube the depth of the dip increased and the first formant peak either changed in frequency or was split by the dip. Only marginal effects were observed of the paranasal sinuses. For certain coupling tube sizes, the spectrum balance was changed, boosting the formant peaks in the 2 - 4 kHz range.

CONCLUSION

A velopharyngeal opening introduces a dip in the transfer function at the main resonance of the nasal tract. Its depth increases with the area of the opening and its frequency rises in some vowels.

The Reliability of Visual Ratings of Velopharyngeal Physiology for Speech

BACKGROUND

Analyze intrarater and interrater reliability for evaluating endoscopic images of velopharyngeal (VP) physiology.

METHOD

Speakers produced 9 speech stimuli representing 4 stimulus types: sustained phonemes, repetitions of "puh," single words, and short phrases. The 37-speaker participants included 16 patients with VP dysfunction and 21 control participants. Five raters independently rated the video images for degree of VP opening, location of opening, and pattern of closure. Outcome measures included intrarater and interrater measures of reliability and the effects of raters and stimulus type on ratings.

RESULTS

Intrarater reliability was acceptable, and ratings were logically consistent. Fixed effects regression coefficients for the patient and the control groups showed that raters were a significant source of variability for degree of opening and pattern of closing. Stimulus type was not a significant source of variation for any metric for the controls, but stimulus type was a significant determinant for degree of opening for patients. The degree of opening was larger for sustained phonemes than for the other speech stimuli. Ratings for degree of opening were most similar for repeated "puh."

CONCLUSIONS

Interrater reliability needs to be improved so that the assessment procedure produces more consistent findings among clinicians, thus strengthening our evidence base for this procedure. Interrater additional research is needed to understand how the stimulus affects ratings of VP physiology, to identify stimuli that yield the most useful clinical information, and to understand how training affects the ratings of VP physiology.

Differences in nasalance and nasality perception between Texas South and Midland dialects

While previous research has primarily concerned the dialectal influence on speakers' production of oral-nasal balance, quantitatively represented by nasalance, information on cross-dialectal variation in nasality perception is limited. This study investigated the effects of speakers'/listeners' dialectal background on oral-nasal balance characteristics estimated by nasalance, as well as nasality perception measured by direct magnitude estimation with modulus. Represented by two geographically distinct regions, Texas South and Midland dialects were of special interest given that the two dialects lie at opposite ends of normal nasalance variation [Awan, Bressmann, Poburka, Roy, Sharp, and Watts. (2015). J. Speech Lang. Hear. Res. 58, 69-77]. Mean nasalance of various speech stimuli and direct magnitude estimation ratings on synthesized vowel stimuli with varying degrees of simulated nasalization were obtained from 62 participants (31 Texas South, 31 Midland). The results revealed that the two dialectal groups significantly differed in nasalance scores and nasality ratings, with Texas South exhibiting higher nasalance for standardized passage readings and assigning higher nasality ratings on the synthetic auditory stimuli than Midland. These findings indicate that, in addition to production variations of oral-nasal balance characteristics, perceptual variations of nasality exist at a dialectal level.

Sound production mechanisms of audible nasal emission during the sibilant /s/

Audible nasal emission is a speech disorder that involves undesired sound generated by airflow into the nasal cavity during production of oral sounds. This disorder is associated with small-to-medium sized velopharyngeal openings. These openings induce turbulence in the nasal cavity, which in turn produces sound. The purpose of this study is to examine the aeroacoustic mechanisms that generate turbulent sound during production of a sibilant /s/ with and without a small opening of the velopharyngeal valve. The models are based on two pediatric subjects who were diagnosed with severe audible nasal emission. The geometries were delineated from computed tomography scans taken while the subjects were sustaining a sibilant sound. Large eddy simulation with the Ffowcs Williams and Hawkings analogy was used to predict the flow behavior and its acoustic characterization. It shows that the majority of the acoustic energy is produced by surface loading, which is related to dipole sources that resonate in the nasal cavity. The quadrupole source term that is associated with the unsteady shear layers is seen to be less significant. It also shows that closure of the velopharyngeal valve changes the far-field spectrum significantly because aeroacoustic mechanisms in the nasal cavity are eliminated.

Effects of regional dialect on oral-nasal balance and nasality perception

While cross-dialectal variations in nasalance have been investigated in previous studies, the influence of regional dialect on listeners' perceptual ratings of nasality has received limited research attention. This study explored cross-dialectal differences in the production of oral-nasal balance and the perception of nasality, with special emphasis on Inland North (IN) and Midland (M) dialects in the USA. Twenty-six adults representing the IN (n = 15) and M (n = 11) dialects participated in the study. Oral-nasal balance characteristics and nasality perception were compared between dialects using mean nasalance of various speech stimuli, measured via nasometry, and perceptual ratings of nasality of synthetic vowel stimuli, measured using direct magnitude estimation (DME). Despite similar mean nasalance scores between two regional dialects for standardized passage readings and sustained vowels, IN and M groups significantly differed in their perceptual ratings of nasality, with the DMEs of IN listeners being consistently and significantly higher, i.e. more nasal, than those of M listeners. Our findings provide evidence for perceptual variations of nasality that may exist at a dialectal level in addition to cross-linguistic variations in the perception of nasality as reported by Lee et al. (2008). Further research is needed to determine to what extent perceptual variations of nasality exist in other dialects and how these variations manifest in perceptual judgments of hypernasality and its severity ratings.

Effects of nasal port area on perception of nasality and measures of nasalance based on computational modeling

OBJECTIVE

This study examined the relation between nasal port area, nasalance, and perceptual ratings of nasality for three English corner vowels, /i/, /u/, and /a/.

DESIGN

Samples were simulated using a computational model that allowed for exact control of nasal port size and direct measures of nasalance. Perceptual ratings were obtained using a paired stimulus presentation.

PARTICIPANTS

Four experienced listeners.

MAIN OUTCOME MEASURES

Nasalance and perceptual ratings of nasality.

RESULTS

Findings show that perceptual ratings of nasality and nasalance increased for samples generated with nasal port areas up to and including 0.16 cm(2) but plateaued in samples generated with larger nasal port areas. No vowel differences were noted for perceptual ratings.

CONCLUSIONS

This work extends previously published work by including nasal port areas representative of those reported in the literature for clinical populations. Continued work using samples with varied phonetic context and varying suprasegmental and temporal characteristics are needed.

Nasalization Amplitude-Timing Characteristics of Speakers With and Without Cleft Palate

OBJECTIVES

To examine the amplitude-temporal relationships of acoustic nasalization in speakers with a range of nasality and to determine the extent to which each domain independently predicts the speaker's perceived oral-nasal balance.

DESIGN

Rate-controlled speech samples, consisting of /izinizi/, /azanaza/, and /uzunuzu/, were recorded from 18 participants (14 with repaired cleft palate and 4 without cleft palate) using the Nasometer. The mean nasalance of the entire mid-vowel-nasal consonant-vowel (mid-VNV) sequence (amplitude-domain) and the duration of the nasalized segment of the mid-VNV sequence (temporal-domain) were obtained based on nasalance contours.

RESULTS

Strong linear and vowel-dependent relationships were observed between the 2 domains of nasalization (adjusted R² = 71.5%). Both the amplitude- and temporal-domain measures were found to reliably predict the speaker's perceived oral-nasal balance, with better overall model fit and higher classification accuracy rates observed in /izinizi/ and /uzunuzu/ than in /azanaza/. Despite poor specificity, the temporal-domain measure of /azanaza/ was found to have a strong correlation with the participants' Zoo passage nasalance scores (r_s = .897, p < .01), suggesting its potential utility as a severity indicator of perceived nasality.

CONCLUSIONS

With the use of relatively simple speech tasks and measurements representing the amplitude and temporal domains of nasalization, the present study provided practical guidelines for using the Nasometer in assessing patients with oral-nasal resonance imbalance. Findings suggest that both domain measures of nasalization should be examined across different vowel contexts, given that each domain may provide clinically relevant, yet different, information.

Speech outcomes in children with 22q11.2 deletion syndrome following surgery for velopharyngeal insufficiency

OBJECTIVE

The purpose of this study was to identify prognostic factors associated with improved speech outcomes following surgical correction for velopharyngeal insufficiency (VPI) in pediatric patients with 22q11.2 deletion syndrome (22q11DS).

METHODS

Eighteen patients were identified via retrospective chart review of patients with 22q11DS between 2005 and 2014. Patient characteristics, medical histories, associated comorbidities, surgical procedures, and pre- and postoperative perceptual hypernasality (subjectively rated 1-5 with 5 being the most severe) were gathered for each patient.

RESULTS

12 patients (67%) experienced improvement in hypernasality following corrective surgery for VPI. Higher severity of hypernasality preoperatively was found to be indicative of a lower chance of improvement with VPI surgery. Of 8 patients with a preoperative hypernasality score of 5, 3 (38%) showed improvement in hypernasality postoperatively, while 9 out of 10 (90%) of patients with a preoperative hypernasality score less than 5 showed postoperative improvement. Females were also found to have worse speech outcomes compared to males.

CONCLUSION

22q11DS patients presenting with severely hypernasal speech preoperatively are less likely to show improvement in hypernasality following corrective surgery for VPI. Those patients with moderate hypernasality are most likely to benefit from surgery.

An Optimal Set of Flesh Points on Tongue and Lips for Speech-Movement Classification

PURPOSE

The authors sought to determine an optimal set of flesh points on the tongue and lips for classifying speech movements.

METHOD

The authors used electromagnetic articulographs (Carstens AG500 and NDI Wave) to record tongue and lip movements from 13 healthy talkers who articulated 8 vowels, 11 consonants, a phonetically balanced set of words, and a set of short phrases during the recording. We used a machine-learning classifier (support-vector machine) to classify the speech stimuli on the basis of articulatory movements. We then compared classification accuracies of the flesh-point combinations to determine an optimal set of sensors.

RESULTS

When data from the 4 sensors (T1: the vicinity between the tongue tip and tongue blade; T4: the tongue-body back; UL: the upper lip; and LL: the lower lip) were combined, phoneme and word classifications were most accurate and were comparable with the full set (including T2: the tongue-body front; and T3: the tongue-body front).

CONCLUSION

We identified a 4-sensor set--that is, T1, T4, UL, LL--that yielded a classification accuracy (91%-95%) equivalent to that using all 6 sensors. These findings provide an empirical basis for selecting sensors and their locations for scientific and emerging clinical applications that incorporate articulatory movements.

Phrase-level speech simulation with an airway modulation model of speech production

Artificial talkers and speech synthesis systems have long been used as a means of understanding both speech production and speech perception. The development of an airway modulation model is described that simulates the time-varying changes of the glottis and vocal tract, as well as acoustic wave propagation, during speech production. The result is a type of artificial talker that can be used to study various aspects of how sound is generated by humans and how that sound is perceived by a listener. The primary components of the model are introduced and simulation of words and phrases are demonstrated.