Glottic Research Articles

Sound source locations and their roles in Japanese voiceless "glottal" fricative production.

Although [h] is described as a glottal fricative, it has never been demonstrated whether [h] has its source exclusively at the glottis. In this study, sound source locations and their influence on sound amplitudes were investigated by conducting mechanical experiments and airflow simulations. Vocal tract data of [h] were obtained in three phonemic contexts from two native Japanese subjects using three-dimensional static magnetic resonance imaging (MRI). Acrylic vocal tract replicas were constructed, and the sound was reproduced by supplying airflow to the vocal tracts with adducted or abducted vocal folds. The sound source locations were estimated by solving the Navier-Stokes equations. The results showed that the amplitudes of sounds produced by the vocal tracts with an open glottis were in a similar range (±3 dB) to those with a glottal gap of 3 mm in some contexts. The sound sources in these cases were observed in the pharyngeal cavity or near the soft palate. Similar degrees of oral constrictions were observed in the real-time MRI, indicating that the sound traditionally described as [h] is produced, at least in some contexts, with sound sources of turbulent flow generated by a supralaryngeal constriction of the following vowel.

Outcome Disparities in Patients with Early-Stage Laryngeal Cancer Depending on Localization, Tobacco Consumption, and Treatment Modality.

Background/Objectives: Laryngeal squamous cell carcinoma (LSCC) is among most frequent malignancies of the head and neck. Recent oncologic research focusses on advanced rather than on early stages. Thus, we aimed to improve the knowledge concerning prognostic factors and survival in early glottic (GC) and supraglottic cancer (SGC). Methods: We retrospectively investigated patients diagnosed in 2007 to 2020 with stage I or II GC (ICD-10-C32.0) or SGC (ICD-10-C32.1, C32.8 or C32.9). For precise discrimination of GC and SGC, pathology reports about biopsy and definitive excision were closely examined and information on clinical characteristics and risk factors were collected before analyzing patterns of risk factors for overall survival (OS) in multivariate Cox regression analyses (mvCox). Results: The cohort included 220 patients with early GC (n = 183) and SGC (n = 37). The GC patients showed significantly improved 5-year OS compared to SGC patients (83.6% vs. 64.9%; p = 0.004), whereas survival according to UICC stage (I vs. II) was not different (p = 0.177). Surgical resection was superior to definitive radiotherapy (RT) for 5-year OS (p < 0.001). Cumulative tobacco consumption of greater than 10 pack years drastically impaired OS (p = 0.024), especially in patients receiving RT (p < 0.001). Supraglottic localization, smoking, and re-resection after initial R1 status consistently were independent prognostic factors in mvCox. Conclusions: Our cohort of early LSCC patients demonstrates significant negative impact of supraglottic localization, older age, tobacco consumption, poor tumor differentiation, and re-resection on OS. Further research is required as there is still lack of evidence on optimal decision-making and therapeutic strategies.

Hiccup Relief Using Active Prolonged Inspiration.

Background Hiccups are a common physiologic reflex resulting from intermittent and involuntary spasmodic contraction of the diaphragm and intercostal muscles. While most cases are self-limited, lasting less than 48 hours, rare pathologies may result in prolonged symptoms. Hiccups can be disruptive and uncomfortable, leading many to seek management strategies using common home remedies. Few methods for terminating hiccups have been published in the scientific literature. We report the efficacy of the Hiccup relief using Active Prolonged Inspiration (HAPI) technique, which combines phrenic and vagal nerve stimulation with transient hypercapnia for hiccup relief. Methods Twenty patients with self-limited hiccups and one patient with prolonged hiccups were successful in eliminating hiccups using HAPI. In this method, patients are instructed to inspire maximally. Once at the peak of inspiration, they continue to attempt to inspire with an open glottis for a total of 30 seconds. This is followed by a slow expiration and resumption of normal respiration. Results In all cases, patients reported immediate hiccup relief. Conclusion These findings suggest the HAPI technique is a simple and viable method for hiccup relief. Further studies are needed to validate effectiveness.

Flow-induced oscillations of vocal-fold replicas with tuned extensibility and material properties

Human vocal folds are highly deformable non-linear oscillators. During phonation, they stretch up to 50% under the complex action of laryngeal muscles. Exploring the fluid/structure/acoustic interactions on a human-scale replica to study the role of the laryngeal muscles remains a challenge. For that purpose, we designed a novel in vitro testbed to control vocal-folds pre-phonatory deformation. The testbed was used to study the vibration and the sound production of vocal-fold replicas made of (i) silicone elastomers commonly used in voice research and (ii) a gelatin-based hydrogel we recently optimized to approximate the mechanics of vocal folds during finite strains under tension, compression and shear loadings. The geometrical and mechanical parameters measured during the experiments emphasized the effect of the vocal-fold material and pre-stretch on the vibration patterns and sounds. In particular, increasing the material stiffness increases glottal flow resistance, subglottal pressure required to sustain oscillations and vibratory fundamental frequency. In addition, although the hydrogel vocal folds only oscillate at low frequencies (close to 60 Hz), the subglottal pressure they require for that purpose is realistic (within the range 0.5–2 kPa), as well as their glottal opening and contact during a vibration cycle. The results also evidence the effect of adhesion forces on vibration and sound production.

An Euler–Bernoulli-type beam model of the vocal folds for describing curved and incomplete glottal closure patterns

Incomplete glottal closure is a laryngeal configuration wherein the glottis is not fully obstructed prior to phonation. It has been linked to inefficient voice production and voice disorders. Various incomplete glottal closure patterns can arise and the mechanisms driving them are not well understood. In this work, we introduce an Euler–Bernoulli composite beam vocal fold (VF) model that produces qualitatively similar incomplete glottal closure patterns as those observed in experimental and high-fidelity numerical studies, thus offering insights into the potential underlying physical mechanisms. Refined physiological insights are pursued by incorporating the beam model into a VF posturing model that embeds the five intrinsic laryngeal muscles. Analysis of the combined model shows that co-activating the lateral cricoarytenoid (LCA) and interarytenoid (IA) muscles without activating the thyroarytenoid (TA) muscle results in a bowed (convex) VF geometry with closure at the posterior margin only; this is primarily attributed to the reactive moments at the anterior VF margin. This bowed pattern can also arise during VF compression (due to extrinsic laryngeal muscle activation for example), wherein the internal moment induced passively by the TA muscle tissue is the predominant mechanism. On the other hand, activating the TA muscle without incorporating other adductory muscles results in anterior and mid-membranous glottal closure, a concave VF geometry, and a posterior glottal opening driven by internal moments induced by TA muscle activation. In the case of initial full glottal closure, the posterior cricoarytenoid (PCA) muscle activation cancels the adductory effects of the LCA and IA muscles, resulting in a concave VF geometry and posterior glottal opening. Furthermore, certain maneuvers involving co-activation of all adductory muscles result in an hourglass glottal shape due to a reactive moment at the anterior VF margin and moderate internal moment induced by TA muscle activation. These findings have implications regarding potential laryngeal maneuvers in patients with voice disorders involving imbalances or excessive tension in the laryngeal muscles such as muscle tension dysphonia.

Towards image-based laryngeal videostroboscopy using deep learning-enabled compressed sensing

Laryngeal videostroboscopy is an audio-mediated imaging technique allowing the visualization of vocal fold oscillation behavior: the audio signal is used to determine the fundamental frequency F0, which represents the vocal fold oscillation frequency. Knowing F0 allows to trigger the strobe illumination unit to provide a still image or slow-motion view of the vocal fold oscillation. However, this procedure involves several hardware components, noisy audio signals, and a chain of complex, error-prone algorithms that have to be orchestrated. We hypothesize that endoscopic images suffice to determine F0 with a view towards providing an alternative, image-based approach for estimating F0 during laryngeal videoendoscopy. In this study, we show that we are able to predict the relative glottal opening state to create sample points on the glottal area waveform, an endoscopic image-derived signal capable of deriving F0. As imaging frame rates from ordinary endoscopic cameras do not fulfill the Shannon–Nyquist criterion, we solve this problem with compressed sensing. We developed and evaluated the proposed approach using high-speed videoendoscopy (HSV) to simulate different, realistic low frame rates that are similar to those used in videostroboscopy. We show that we are able to predict F0 with over 95% accuracy using at most 75 sample points of a 600 ms long footage. Using endoscopic images and our algorithm only, we showcase that we can achieve a stroboscopic effect. This shows, that our proposed method in combination with the developed algorithm may be considered in the future to be integrated into clinical videostroboscopy.

Enhanced Abductor Function in Bilateral Vocal Fold Paralysis with Muscle Stem Cells.

Patients with bilateral vocal fold paralysis (BVFP) experience airway obstruction because of loss of abductor function of posterior cricoarytenoid (PCA) muscles. We previously reported that implantation of autologous muscle progenitor (stem) cells into thyroarytenoid muscles during reinnervation resulted in improved adductor function. In this study, that same approach was applied to treating PCA muscles in a canine model of BVFP. Animal study. Two canines underwent baseline measures of glottal resistance (GR), then complete transection and suture repair of both recurrent laryngeal nerves. Muscle stem cells were isolated from skeletal muscle and cultured. Two months later, GR was measured, and then 107 stem cells were implanted into one PCA muscle of each animal. After four more months, GR and glottal opening force (GOF) were measured and the muscles were harvested for histologic study. One control dog underwent the same procedures without stem cell implantation, for comparison. GR increased by 21%-25% over baseline at 2 months, but after stem cell implantation, improved to 10%-14% over baseline at 6 months. PCA muscle strength, as determined by GOF, was 61%-65% on control sides (no stem cells), and 78%-83% on treated sides (with stem cells). Histology confirmed survival of stem cells and a 50% higher rate of innervation of motor endplates in the stem cell treated sides. Autologous muscle progenitor (stem) cells show promise as a potential new therapy for patients with bilateral vocal fold paralysis. Additional studies are needed to determine the optimal number of cells, timing of implantation, and other variables before launching a clinical trial. NA (animal study) Laryngoscope, 134:324-328, 2024.

High-Speed Image Analysis Comparing Loading of Vocal Folds During Coughing and Phonation: A Case Study

Coughing is related to voice problems, since it involves firm glottal closure, fast glottal opening, and high subglottic pressure and flow rate. In this study, the glottal area variation and movements of laryngeal structures during coughing and phonation are compared. High-speed laryngoscopy recordings were made of a normophonic male participant with a healthy larynx producing a neutral vowel and coughing. Oral air pressure was registered in a mouthpiece, through which an endoscope was inserted into the pharynx. Electroglottography, acoustic, and pressure signals were recorded simultaneously. The glottal width variation at the membranous and cartilaginous parts of the glottis was derived from the high-speed images, and the strong vibration of the false vocal folds was also registered. In coughing, compared to ordinary vowel phonation in nearly the same sound pressure level (93-94 dB6cm), the glottal width was 25% larger at the middle of the vocal folds, the maximum glottal opening velocity was 39% higher, and the maximum glottal width declination rate during glottal closing was up to three times higher. The maximum acceleration was 40% higher, and the maximum deceleration was 47% higher. Fundamental frequency f0 was the highest (ca. 400 Hz) at the beginning of the first phase of a typical coughing process. During the last part of the coughing process, f0 decreased from ca. 250 Hz to ca. 85 Hz at the phonation offset. The remarkable increase in maximum glottal width declination rate implies much higher vocal fold loading in coughing compared to phonation.

Combining Artificial Intelligence and Automatic Analysis to Study of the Closure Characteristics of Healthy Human Vocal Cords during Phonation Using Synchronous Electroglottography and Laryngeal High-Speed Videoendoscopy

To use an artificial intelligence neural network to automatically analyze images from high-speed videoendoscopy and synchronous electroglottographic signals in healthy vocal folds to obtain the accurate glottal opening and closing instants in the glottal cycle.

Surgical Techniques for Glottal Airway Enlargement -Laterofixation of the Vocal Fold-

Glottal airway enlargement is required to manage dyspnea due to bilateral vocal fold paralysis (BVFP). The method of vocal fold laterofixation reported by Ejnell et al. is relativly non-invasive and has been considered the first choice in cases of BVFP in recent years. We used a video-laryngoscope to obtain a better endolaryngeal view and a GORE-TEX® Soft Tissue Patch as a spacer between the thyroid lamina and the nylon knot to prevent loosening. Laryngeal pacing is a more dynamic and physiologic treatment approach than static airway enlargement procedures, such as laterofixation of the vocal fold. Laryngeal pacing is the application of functional electrical stimulation (FES) of the laryngeal abductor muscles. We evaluated the efficacy of FES in restoring glottal opening, ventilation, and exercise tolerance in a BVFP canine model. An implantable stimulator and deep brain stimulation electrodes were surgically implanted into both posterior cricoarytenoid (PCA) muscles in the animal, and the bilateral recurrent laryngeal nerves were sectioned and repaired. Beyond three months postoperatively, there was passive airway narrowing and further closure of the glottis during hypercapnia. The animal showed severe stridor and could only walk for one to two minutes on a treadmill. With the stimulation-on condition, the glottal area increased considerably, equaling that of a normally innervated animal. Exercise tolerance also returned to normal. Bilateral PCA stimulation offers a physiologic approach to restore ventilation to a normal level in cases of BVFP.

Dosimetric Predictors of Acute and 1-Year Functional Oral Intake for Head and Neck Cancer Patients Treated with Radiotherapy

<h3>Purpose/Objective(s)</h3> In order to reduce risks of radiation-induced dysphagia after head and neck radiotherapy, a better understanding of the relationship between dose to various swallowing-related organs at risk (SOARs) is necessary. There is limited data regarding the association of 6–12-month functional swallowing outcomes and the dose to SOARs including the pharyngeal constrictor muscle (PC), cricopharyngeus (C), glottic (GL) supraglottic larynx (SGL), and the RTOG-defined Pharynx OAR (POAR). We assessed dosimetric predictors of change in swallowing function from up to 1-year post-RT. <h3>Materials/Methods</h3> We retrospectively reviewed our institutional database of patients treated with head and neck cancer from 2017-2020. Swallowing function was assessed at 1-, 3-, 6-, and 12-months post-treatment using the Functional Oral Intake Scale (FIOS, 1=no oral intake, 7=total oral intake without restrictions). Mean dose, V50, and V60 were abstracted from the treatment planning software for each SOAR. Patients were categorized by whether clinically relevant constraint parameters were met for each SOAR, which were then evaluated for association with FOIS using the Wilcoxon test. <h3>Results</h3> In total, 141 patients with evaluable treatment plans and swallowing outcomes were analyzed. Of the patients included for analysis, 51% had oropharyngeal cancer, 100% received concurrent chemotherapy, and 31% were treated post-operatively. Across all included treatment plans, the median prescribed dose to PTV was 70 Gy (38-70 Gy). Swallowing outcomes at 1-, 3-, 6-, and 12-months post-treatment were available for 132 (94%), 129 (91%), 121 (86%), and 111 (79%) patients, respectively. The median (range) FOIS scores at baseline, 1-, 3, 6-, and 12-months were 7 (5-7), 4 (2-7), 6 (3-7), and 7 (6-7). For each swallowing structure the mean (Gy) doses (listed as median (IQR)) were: 57.7 (49.0-64.3) for PC, 47.3 (38.7-51.4) for C, 38.9 (33.6-43.4) for GL, 47.4 (38.8-52.2) for SGL, and 53.2 (45.4-59.5) for POAR. The V50 (%) for each SOAR was: 77.5% (52.6-93.5) for PC, 23.3% (5.1-59.8) for C, 0.2% (0-5.1) for GL, 36.4% (19.5-48.5) for SGL, and 67.3% (42.8-86.6) for POAR. The V60 (%) for each SOAR was: 47.5% (23.0-75.5) for PC, 0.5% (0-8.6) for C, 0% (0-0) for GL, 21.4% (4.2-34.5) for SGL, and 32.2% (8.3-55.7) for POAR. On dosimetric analysis, PC mean≤50Gy, POAR mean≤45Gy, and POAR V50<33% were associated with increased FOIS at 1- and 3-months (p<0.05). POAR V60<15% and SGL mean<=40Gy was associated with FOIS at 1-mo (p<0.05). No evaluated factors were associated with 6- or 12-month FOIS. <h3>Conclusion</h3> Lower doses of radiation to pharyngeal constrictor, RTOG-defined pharynx, and supraglottic larynx are associated with improved swallowing function in patients with head and neck cancer. Radiation treatment plans should be optimized to reduce dose to these structures in order to improve acute swallowing outcomes. A larger sample size is needed to better evaluate the impact of radiation dose to these structures on long term swallowing outcomes.

Near-infrared photoglottography for measuring multiple glottal events.

Near-infrared (NIR) photoglottography (PGG) is a non-invasive method for monitoring glottal activities which retains functionality of conventional PGG using visible light with more convenient accessibility. This paper is to investigate its performance in comparison with simultaneously recorded electroglottography (EGG) signals. Results showed that NIR PGG detects continuous transillumination for glottal aperture and vocal-fold contact. Glottal timing markers known as glottal closure and opening instants are detectable agreeing to the corresponding EGG-based instants. Further, it was inferred that variations of glottal waveforms based on NIR PGG reflect vertical vocal-fold edge motions.

External photoglottography, intra-oral air pressure, airflow and acoustic data on the Korean fricatives /s’, s/

From simultaneous recordings of the external photoglottography, intra-oral air pressure (P_io), airflow and acoustic data from four native Seoul Korean speakers (2 male and 2 female), we have found that the two fricatives are not significantly different in glottal opening peak and airflow peak height either word-initially or word-medially and that the duration of aspiration is significantly reduced in word-medial /s/, compared to those in word-initial /s/, not in /s’/. We have also found that the duration of a high P_io plateau is significantly longer in /s/ than in /s’/ both word-initially and word-medially and that airflow resistance (R=P_io/U) at the onset and offset of a P_io plateau and at the time of airflow peak height is significantly higher in /s’/ than in /s/ across the contexts. However, the differences in P_io peak and F0 are not significant. In addition, the transition time to reach airflow peak height from the offset of a P_io plateau is found to be significantly longer in /s/ than /s’/ in both word-initial and word-medial positions. No significant differences in glottal opening peak and airflow peak height confirm that /s/ is specified as [–spread glottis] like /s’/. As for the other significant differences, we propose that /s/ is [–tense], and /s’/ [+tense].

Collision Pressure and Dissipated Power Dose in a Self-Oscillating Silicone Vocal Fold Model With a Posterior Glottal Opening.

The goal of this study was to experimentally evaluate how compensating for the adverse acoustic effects of a posterior glottal opening (PGO) by increasing subglottal pressure and changing supraglottal compression, as have been associated with vocal hyperfunction, influences the risk of vocal fold (VF) trauma. A self-oscillating synthetic silicone model of the VFs with an airflow bypass that modeled a PGO was investigated in a hemilaryngeal flow facility. The influence of compensatory mechanisms on collision pressure and dissipated collision power was investigated for different PGO areas and supraglottal compression. Compensatory behaviors were mimicked by increasing the subglottal pressure to achieve a target sound pressure level (SPL). Increasing the subglottal pressure to compensate for decreased SPL due to a PGO produced higher values for both collision pressure and dissipated collision power. Whereas a 10-mm2 PGO area produced a 12% increase in the peak collision pressure, the dissipated collision power increased by 122%, mainly due to an increase in the magnitude of the collision velocity. This suggests that the value of peak collision pressure may not fully capture the mechanisms by which phonotrauma occurs. It was also found that an optimal value of supraglottal compression exists that maximizes the radiated SPL, indicating the potential utility of supraglottal compression as a compensatory mechanism. Larger PGO areas are expected to increase the risk of phonotrauma due to the concomitant increase in dissipated collision power associated with maintaining SPL. Furthermore, the risk of VF damage may not be fully characterized by only the peak collision pressure.

Production and Perception of Mandarin Laryngeal Contrast: The Role of Post-plosive F0

This study examines the relation between plosive aspiration and post-plosive f0 (fundamental frequency) in the production and perception of the laryngeal contrast in Mandarin. Production data from 25 Mandarin speakers showed that, in word onsets, VOTs (voice onset time) of aspirated and unaspirated plosives were different, as expected. At the same time, the speakers produced different post-plosive f0 between aspirated and unaspirated plosives, but the difference varied according to the lexical tones – post-aspirated f0 was higher than post-unaspirated f0 in high-initial tones (i.e., lexical tones with high onset f0), but the pattern was the opposite and less robust in low-initial tones. In the perception of the same participants, VOT was the primary cue to aspiration but, when VOT was ambiguous, high post-plosive f0 yielded more aspirated responses in general. We claim that the asymmetry in f0 perturbation between high-initial and low-initial tones in production arises from different laryngeal maneuvers for different tonal targets. In low-initial tones, in which the vocal folds are slack and the glottal opening is wider, aspirated plosives have a lower subglottal air pressure than unaspirated plosives at the voicing onset, resulting in lower post-aspirated f0 than post-unaspirated f0. But in high-initial tones, the vocal folds are tense, which requires a higher trans-glottal pressure threshold to initiate phonation at the onset of voicing. As a result, the subglottal pressure does not decrease as much. Instead, the faster airflow in aspirated than unaspirated plosives gives rise to the pattern that post-aspirated f0 is higher than post-unaspirated f0. Regardless of this variation in production, our perception data suggest that Mandarin listeners generalize the f0 perturbation patterns from high-initial tones and associate high post-plosive f0 with aspirated plosives even in low-initial tone contexts. We cautiously claim that the observed perceptual pattern is consistent with the robustly represented production pattern, as high-initial tones are more prevalent and salient in the language and exhibit stronger f0 perturbation in the speakers' productions.

Vocalization during the second stage of labor to prevent perineal trauma: A randomized controlled trial

Background and purposeMost women suffer some degree of perineal trauma during vaginal delivery. Second stage management strategies, including vocalization, to protect the perineum have been investigated. Objective: To compare the frequency and degree of perineal trauma at vaginal delivery, with and without use of the vocalization maneuver during the second stage of labor. Materials and methodsThis is an open-label, randomized controlled trial. We conducted the study at the Center for Normal Deliveries of IMIP. We included low-risk women without prior cesarean deliveries. Women who met the inclusion criteria and signed the informed consent form were randomized to one of two groups: Group A (experimental) and Group B (control). A physical therapist encouraged women in Group A to maintain an open glottis during pushing and to emit sounds when exhaling (vocalization). Women in Group B underwent routine humanized vaginal deliveries. The outcomes of the study were perineal integrity and degree of perineal laceration. These were measured by the study team immediately after completion of the third stage of labor. Results: Women in Group A tended to have less severe perineal tear (less second and third degree lacerations) and smaller lacerations than women in group B. The vocalization maneuver reduced the risk of a perineal tear greater than 2 cm by 68% (NNT 2.2). There was no difference in other outcomes. ConclusionEncouraging women to follow a vocalization protocol coached by a physical therapist during the second stage of labor can be a helpful labor assistance technique, since this study showed that vocalization is associated with less extensive perineal tears. Clinical Trial RegistrationThis study was registered on ClinicalTrials.gov (www.clinicaltrial.gov) registration number: NCT03605615.

Computational Study of the Impact of Dehydration-Induced Vocal Fold Stiffness Changes on Voice Production

Systemic vocal fold dehydration is known to increase vocal fold stiffness, which has been hypothesized to have important effect on voice production. However, it remains unclear whether the dehydration-induced vocal fold stiffness changes can have a noticeable impact on phonation, particularly in normal phonation conditions. The goal of this study was to investigate the impact of vocal fold stiffness changes due to vocal fold systemic dehydration and its significance in daily communication. Parametric computational simulation using a three-dimensional vocal fold model, in which the vocal fold stiffness was varied as a function of systemic dehydration levels based on previously-reported experimental data. The results showed that systemic dehydration had significant effects on voice production only at high levels of dehydration, at which dehydration increased the phonation threshold pressure and fundamental frequency, and decreased glottal opening area, vocal intensity and glottal efficiency. The effect depended mainly on the overall dehydration level but was also slightly affected by the dehydration distribution and muscular control. However, for dehydration levels typical of normal phonation conditions, the effect was negligible. The results indicated that dehydration-induced vocal fold stiffness change likely is not an important mechanism through which vocal fold systemic dehydration affects voice production. Nevertheless, a large decrease in glottal efficiency implies a possible perceived increase of vocal effort under a realistic dehydration condition.

Effect of Open Glottis versus closed Glottis (Valsalva) in Second Stage of Labor on Maternal and Neonatal Outcomes

Effect of Open Glottis versus closed Glottis (Valsalva) in Second Stage of Labor on Maternal and Neonatal Outcomes

Vocal Tract and Subglottal Impedance in High Performance Singing: A Case Study

The respiratory process is important in vocal training and in professional singing, the airflow is highly important. It is hypothesized that subglottal resonances are important to the singing voice in high performance singing. Single subject, prospective. A professional soprano singer shaped her vocal tract to form the vowels [a], [e], [i], [o], and [u] at the pitch d4. We measured phonated vowels and the vocal tract impedance spectra with a deterministic noise supplied by an iPhone buzzer in the range of 200 to 4,000 Hz at closed glottis, during exhalation and during inhalation while maintaining the shape of the vocal tract. Measurements of the phonated vowels before and after the different glottal adjustments were highly reproducible. Vocal tract resonances and the ones resulting during respiration are reported. The impedance spectra show vowel dependent resonances with closed and open glottis. The formants of the vocal spectra are explained by including both, the vocal tract, and the subglottal resonances. The findings indicate that subglottal resonances influence the first formant as well as the singers's formant cluster in high-performance singing. The instrumental setup used for the impedance measurement allows a simple and lightweight procedure for a measurement of vocal tract and subglottal resonances.

Acoustic features of palatalized consonants in Nasa Yuwe

Nasa Yuwe a Colombian language spoken in the Cauca presents complex features of palatalization [1,2]. Stops and affricates can be palatalized, aspirated and palatalized-aspirated at all places of articulation while prenasalized consonants and fricatives can only be palatalized. Data for this study were recorded from an acoustic recording session and by combining, in a second phase, synchronized acoustic, EGG and oral airflow recordings from 6 speakers (3 female and 3 male). Results show that all palatalized stops are characterized by a short frication noise at the end and a F3/F4 pole at the start of the following vowel. Aspirated stops have a greater frication noise duration and an open glottis. Palatalized-aspirated stops and affricates are produced with frication noise, a F3/F4 pole at the start of the following vowel and an open glottis. Palatalized-aspirated consonants have two phases: a short and intense frication noise accounting for the palatalization, followed by a lower intensity aspiration noise. Both phases can be distinguished by their FFT spectra and oral airflow volume velocity. Prenasalized consonants behave as palatalized stops but without the aspiration feature. Palatalized fricatives have a resonance during the frication, reflecting a tongue movement towards the palatal place. [1] E. Dias, El Habla Nasa (paez) de Munchique: Nuevos Acercamientos a Su Sociolingüistica, Fonologia y Morfosintaxis (Université Lumière Lyon 2, 2019). [2] T. Rojas, La Lengua Paez (Ministerio de Cultura, Bogota, 1998).