Lip Opening Research Articles

Sketches of chimpanzee (Pan troglodytes) hoo’s: vowels by any other name?

In human speech, the close back rounded vowel /u/ (the vowel in “boot”) is articulated with the tongue arched toward the dorsal boundary of the hard palate, with the pharyngeal cavity open. Acoustic and perceptual properties of chimpanzee (Pan troglodytes) hoo’s are similar to those of the human vowel /u/. However, the vocal tract morphology of chimpanzees likely limits their phonetic capabilities, so that it is unlikely, or even impossible, that their articulation is comparable to that of a human. To determine how qualities of the vowel /u/ may be achieved given the chimpanzee vocal tract, we calculated transfer functions of the vocal tract area for tube models of vocal tract configurations in which vocal tract length, length and area of a laryngeal air sac simulacrum, length of lip protrusion, and area of lip opening were systematically varied. The method described is principally acoustic; we make no claim as to the actual shape of the chimpanzee vocal tract during call production. Nonetheless, we demonstrate that it may be possible to achieve the acoustic and perceptual qualities of back vowels without a reconfigured human vocal tract. The results, while tentative, suggest that the production of hoo’s by chimpanzees, while achieving comparable vowel-like qualities to the human /u/, may involve articulatory gestures that are beyond the range of the human articulators. The purpose of this study was to (1) stimulate further simulation research on great ape articulation, and (2) show that apparently vowel-like phenomena in nature are not necessarily indicative of evolutionary continuity per se.

Dynamic changes of vocal tract dimensions with sound pressure level during messa di vocea).

The messa di voce (MdV), which consists of a continuous crescendo and subsequent decrescendo on one pitch is one of the more difficult exercises of the technical repertoire of Western classical singing. With rising lung pressure, regulatory adjustments both on the level of the glottis and the vocal tract are required to keep the pitch stable. The dynamic changes of vocal tract dimensions with the bidirectional variation of sound pressure level (SPL) during MdV were analyzed by two-dimensional real-time magnetic resonance imaging (25 frames/s) and synchronous audio recordings in 12 professional singer subjects. Close associations in the respective articulatory kinetics were found between SPL and lip opening, jaw opening, pharynx width, uvula elevation, and vertical larynx position. However, changes in vocal tract dimensions during plateaus of SPL suggest that perceived loudness could have been varied beyond the dimension of SPL. Further multimodal investigation, including the analysis of sound spectra, is needed for a better understanding of the role of vocal tract resonances in the control of vocal loudness in human phonation.

Consonant and vowel rounding: Same acoustics, different visuals

The phonological feature [±round] is normally associated with vowels, but this feature is also relevant for some consonant contrasts, such as the retroflex/non-retroflex sibilant contrast in Mandarin. One might assume that contrastive lip rounding would be the same gesture for consonants and vowels within language. However, because similar acoustic results can be achieved through different articulations, we hypothesize that the exact parameters of rounding might be variable for different segment types. An audiovisual production experiment was conducted with 30 Mandarin native speakers. Subjects produced 35 words with sibilants onsets (retroflexes /ʂ, ʈʂ, ʈʰ/, alveolars /s, ts, tsʰ/, palatoalveolars /ɕ, tɕ, tɕʰ/), and 40 words with high-front rounded/unrounded nuclei (/i/ and /y/). We found robust individual variation and that consonants and vowels were characterized with different visual properties: /y/ had small aperture in both vertical and horizontal directions and therefore smaller lip opening area than in /i/, while retroflexes had smaller horizontal but larger vertical apertures than alveolars or palatals. Acoustical consequences of rounding were similar: both spectral Center of Gravity and F1–F4 were lowered compared to unrounded counterparts, indicating that the same phonological feature may have multiple visual/articulatory correlates.

Articulatory and Phonatory Precision When Singing Staccato at Different Speeds

Vocal tract adjustments are important for resonatory modification of the voice and also with respect to interactions concerning the voice source production. It is not clear, however, how fast, separated notes (staccato) influence vocal tract adjustments. Twelve professional singers (four sopranos, three mezzo-sopranos, three tenors, and two baritones/basses) were recorded with dynamic real-time 2D-magnetic resonance imaging (MRI) with 25fps singing a scale in legato and different staccato speeds (60, 120, 180, and 240bps). From the MRI material, the lip opening, jaw opening, jaw protrusion, tongue position, pharynx width, and larynx position were measured. Furthermore, the fundamental frequency was analyzed from the simultaneously recorded audio signal after noise cancellation. The data show only very small differences between the legato and the staccato tasks and no great variations for different staccato speeds. During the pauses in between the staccato notes, minimal vocal tract adjustments were only detectable for the slowest staccato task. There are no great differences in the vocal tract shapes for legato singing in contrast to staccato phonation and no great differences for different staccato speeds.

A Study on Lip Movements Area and Vowel Space Area According to the Depressive Disorders

Background and Objectives This study aims to investigate the lip movements area (LMA) and vowel space area according to depression.Materials and Method The participants diagnosed with voice disorders or thyroid cancer before treatment and surgery. All participants completed the depression questionnaire and recorded five vowels (/a, i, u, e, o/) phonation while shooting. Among the total 64 participants, there were 19 participants in the depressive disorders group and 45 participants in non-depressive group. The analysis parameters were LMA, vowel space areas (Area3 & Area5), formant centralization ratio (FCR), fundamental frequency (F0) and voice intensity (intensity). Multivariate analysis of variance (MANOVA) was applied, and age was treated as a covariate to correct for lip movement that could deteriorate as age increased.Results As a result of MANOVA, there was no significant difference between groups (p=0.517). Looking at the LMA, both male and female in the depressive disorder group showed a lower mean value than the non-depressive disorders group. The Area3 and FCR of the depressive disorder group were higher than those in the non-depressive disorders group, whereas for the Area5, the mean value of female in the depressive disorder group was higher than that of the non-depressive disorder group and the male’s non-depressive disorder group had a slightly higher mean value.Conclusion The voice intensity according to the presence or absence of depressive disorder was similar, but the depressive disorder group tended to show narrower oral area with smaller lip opening.

Evaluation of glottal inverse filtering in the presence of source-filter interaction

Glottal inverse filtering is often used to recover the glottal flow waveform from the produced voice outcomes. While there have been many studies aiming to evaluate its validity, few studies investigated its validity in voice conditions with strong source-filter interaction. The goal of this study is to evaluate the performance of glottal inverse filtering in conditions of epilaryngeal tube narrowing and/or reduced lip opening, both of which are expected to enhance source-filter interaction. Computational simulation of voice production was performed using a three-dimensional vocal fold model coupled to a vocal tract with varying degrees of constriction at the epilarynx and lips. Different algorithms of inverse filtering were then used to estimate the glottal airflow waveform from either the produced voice or airflow at the lips, and compared to the true glottal airflow from the simulation. The estimation errors in the glottal flow waveform and selected glottal flow-based measures will be evaluated as a function of the epilaryngeal and lip openings.

Buckling behaviour of FRP strengthened cylindrical metallic shells with cut-outs

This paper presents a detailed buckling study on FRP strengthening of metallic cylindrical shells with different geometric imperfections and centrally located unstiffened and stiffened cut-outs. Initially, bare and FRP strengthened aluminium cylindrical shells have been manufactured. Geometric imperfections have been measured and implemented in the numerical model. Interfacial bond quality has been assessed by two different non-destructive techniques. The buckling response of bare and FRP strengthened shells have been numerically simulated and validated with respective experiments. Subsequently, the difference in buckling response between FRP strengthened and bare aluminium shells with variations in cut-out’s size, orientation, shape, and corner radius has been analysed for unstiffened cut-outs. The effect of increase in stiffener’s thickness and overlap width for photo-frame type stiffening of rectangular cut-outs with and without closure has been investigated. The study has revealed interesting observations. (1) Effect of cut-out size on buckling capacity of the shell is a function of its imperfection magnitude. For shells with large initial imperfections, introducing a cut-out as well as with increase in its size, relatively smaller drop in buckling capacity is found; while shells with small initial imperfections resulted in a steep and large drop in buckling load even with a small cut-out size. (2) FRP strengthening is more effective for shells with cut-outs compared to shells without cut-outs, as it increases the flexural stiffness of shell against asymmetric buckles’ initiation and resists outward lip opening along longitudinal edge of cut-out. (3) For shells with large initial imperfections, elliptical cut-outs offer higher buckling resistance than rectangular cut-outs with varying corner radius but with FRP wrapping, rectangular cut-outs with rounded edges exhibit the best buckling performance. (4) In the case of shells with stiffened cut-out, both with or without closure, FRP strengthening is effective only for shells with smaller initial imperfections. Further findings and observations are discussed and concluded.

Tracing the Phonetic Space of Prosodic Focus Marking.

Focus is known to be expressed by a wide range of phonetic cues but only a few studies have explicitly compared different phonetic variables within the same experiment. Therefore, we presented results from an analysis of 19 phonetic variables conducted on a data set of the German language that comprises the opposition of unaccented (background) vs. accented (in focus), as well as different focus types with the nuclear accent on the same syllable (broad, narrow, and contrastive focus). The phonetic variables are measures of the acoustic and articulographic signals of a target syllable. Overall, our results provide the highest number of reliable effects and largest effect sizes for accentuation (unaccented vs. accented), while the differentiation of focus types with accented target syllables (broad, narrow, and contrastive focus) are more subtle. The most important phonetic variables across all conditions are measures of the fundamental frequency. The articulatory variables and their corresponding acoustic formants reveal lower tongue positions for both vowels /o, a/, and larger lip openings for the vowel /a/ under increased prosodic prominence with the strongest effects for accentuation. While duration exhibits consistent mid-ranked results for both accentuation and the differentiation of focus types, measures related to intensity are particularly important for accentuation. Furthermore, voice quality and spectral tilt are affected by accentuation but also in the differentiation of focus types. Our results confirm that focus is realized via multiple phonetic cues. Additionally, the present analysis allows a comparison of the relative importance of different measures to better understand the phonetic space of focus marking.

Voice source, formant frequencies and vocal tract shape in overtone singing. A case study

Purpose: In overtone singing a singer produces two pitches simultaneously, a low-pitched, continuous drone plus a melody played on the higher, flutelike and strongly enhanced overtones of the drone. The purpose of this study was to analyse underlying acoustical, phonatory and articulatory phenomena. Methods: The voice source was analyzed by inverse filtering the sound, the articulation from a dynamic MRI video of the vocal tract profile, and the lip opening from a frontal-view video recording. Vocal tract cross-distances were measured in the MR recording and converted to area functions, the formant frequencies of which computed. Results: Inverse filtering revealed that the overtone enhancement resulted from a close clustering of formants 2 and 3. The MRI material showed that for low enhanced overtone frequencies (F E) the tongue tip was raised and strongly retracted, while for high F E the tongue tip was less retracted but forming a longer constriction. Thus, the tongue configuration changed from an apical/anterior to a dorsal/posterior articulation. The formant frequencies derived from the area functions matched almost perfectly those used for the inverse filtering. Further, analyses of the area functions revealed that the second formant frequency was strongly dependent on the back cavity, and the third on the front cavity, which acted like a Helmholtz resonator, tuned by the tongue tip position and lip opening. Conclusions: This type of overtone singing can be fully explained by the well-established source-filter theory of voice production, as recently found by Bergevin et al. [1] for another type of overtone singing.

Vocal tract adjustments to minimize vocal fold contact pressure during phonation

This computational study aims to identify vocal tract adjustments that minimize the peak vocal fold contact pressure during phonation and thus should be targeted in voice therapy treating phonotraumatic vocal hyperfunction. The results showed that for a given subglottal pressure, the effect of vocal tract adjustments on the peak vocal fold contact pressure was generally small except when such adjustments caused noticeable changes in the glottal flow amplitude. In this study, this occurred mainly when the lip opening was reduced and at conditions of large initial glottal angles or high subglottal pressures, which decreased the peak contact pressure but also significantly reduced the output sound pressure level (SPL). On the other hand, increasing lip opening significantly increased sound radiation efficiency from the mouth and reduced the subglottal pressure required to produce a target SPL. Because of the large effect of the subglottal pressure on the peak contact pressure, increasing lip opening thus was able to significantly reduce the peak contact pressure in voice tasks targeting a specific SPL. In contrast, the effect of pharyngeal expansion alone had only a small effect on the peak contact pressure, whether controlling for the subglottal pressure or targeting a specific SPL.

The Effect of the Non-circularity of Lip Opening in the Whistle on the Volume

The Effect of the Non-circularity of Lip Opening in the Whistle on the Volume

Articulatory Correlates of Stress Pattern Disturbances in Talkers With Dysarthria.

Purpose Reduced stress commonly occurs in talkers with Parkinson's disease (PD), whereas excessive and equal stress is frequently associated with dysarthria of talkers with amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). This study sought to identify articulatory impairment patterns that underlie these two impaired stress patterns. We further aimed to determine if talkers with the same stress pattern disturbance but different diseases (ALS and MS) exhibit disease-specific articulatory deficits. Method Fifty-seven talkers participated in the study-33 talkers with dysarthria and 24 controls. Talkers with dysarthria were grouped based on their medical diagnosis: PD (n = 15), ALS (n = 10), MS (n = 8). Participants repeated target words embedded in a carrier phrase. Kinematic data were recorded using electromagnetic articulography. Duration, displacement, peak speed, stiffness, time-to-peak speed, and parameter c were extracted for the initial lower lip opening stroke of each target word, which was either stressed or unstressed. Results Stress effects were significant for all kinematic measures across groups except for stiffness and time-to-peak speed, which were nonsignificant in ALS. For comparisons with controls, more kinematic measures significantly differed in the ALS group than in the PD and MS groups. Additionally, ALS and MS showed mostly similar articulatory impairment patterns. Conclusions In general, significant stress effects were observed in talkers with dysarthria. However, stress-specific between-group differences in articulatory performance, particularly displacement, may explain the perceptual impression of disturbed stress patterns. Furthermore, similar findings for ALS and MS suggest that articulatory deficits underlying similar stress pattern disturbances are not disease-specific.

English Pronunciation Standards Based on Multimodal Acoustic Sensors

In recent years, economic globalization is the trend, and communication between countries is getting closer and closer; more and more people begin to pay attention to learning spoken English. The development of computer‐aided language learning makes it more convenient for people to learn spoken English; however, the detection and correction of incorrect English pronunciation, which is its core, are still inadequate. In this paper, we propose a multimodal end‐to‐end English pronunciation error detection and correction model based on audio and video, which does not require phoneme forced alignment of the English pronunciation video signal to be processed, and uses rich audio and video features for English pronunciation error detection, which improves the error detection accuracy to a great extent especially in noisy environments. To address the shortcomings of the current lip feature extraction algorithm which is too complicated and not enough characterization ability, a feature extraction scheme based on the lip opening and closing angle is proposed. The lip syllable frames are obtained by video frame splitting, the syllables are denoised, the key point information of the lips is obtained using a gradient enhancement‐based regression tree algorithm, the effects of speaker tilt and movement are removed by scale normalization, and finally, the lip opening and closing angles are calculated using mathematical geometry, and the lip feature values are generated by combining the angle changes.

Acoustic and articulatory analysis and synthesis of shouted vowels

Acoustic and articulatory differences between spoken and shouted vowels were analyzed for two male and two female subjects by means of acoustic recordings and midsagittal magnetic resonance images of the vocal tract. In accordance with previous acoustic findings, the fundamental frequencies, intensities, and formant frequencies were all generally higher for shouted than for spoken vowels. The harmonics-to-noise ratios and H1-H2 measures were generally lower for shouted vowels than for spoken vowels. With regard to articulation, all subjects used an increased lip opening, an increased jaw opening, and a lower tongue position for shouted vowels. However, the changes of vertical larynx position, uvula elevation, and jaw protrusion between spoken and shouted vowels were inconsistent among subjects. Based on the analysis results, a perception experiment was conducted to examine how changes of fundamental frequency, subglottal pressure, vocal tract shape, and phonation type contribute to the perception of stimuli created by articulatory synthesis as being shouted. Here, fundamental frequency had the greatest effect, followed by vocal tract shape and lung pressure, with no measurable effect of phonation type.

Accuracy, recording interference, and articulatory quality of headsets for ultrasound recordings

In this paper we evaluate the accuracy, recording interference, and articulatory quality of two different ultrasound probe stabilization headsets: a metallic Ultrasound Stabilisation Headset (USH) and UltraFit, a recently developed headset that is 3D printed in Nylon. To evaluate accuracy, we recorded three native speakers of German with different head sizes using an optical marker tracking system that provides sub-millimeter tracking accuracy (NaturalPoint OptiTrack Expression). The speakers had to read C1V1C2V1/2 non-words (to diminish lexical influences) in three conditions: wearing the USH headset, wearing the UltraFit headset, and without a headset. To estimate the relative headset movement, we measured the movement between tracked points on the probe, headset, and speaker’s nose. By also tracking visual marker points on the speaker’s lip and chin, we compared the movement of the outer articulators with and without a headset and, thereby, measured how the headsets interfere with the articulatory space of the speaker. Additionally, we computed the differences in tongue profiles at the acoustic midpoint of V1 under the three conditions and evaluated the articulatory recording quality with a distance index and an area index. In the final evaluation, we also compared formant measurements of recordings with and without headsets. With this objective evaluation we provide a systematic analysis of different headsets for Ultrasound Tongue Imaging (UTI) and also contribute to the discussion of using UTI stabilization headsets for recording natural speech. We show that both headsets have a similar accuracy, with the USH performing slightly better overall but introducing the largest error for one speaker, and that the UltraFit headset shows more flexibility during recordings. Each headset influences the lip opening differently. Concerning the tongue movement, there are no significant differences between different sessions, showing the stability of both headsets during the recordings. Acoustic analysis of formant differences in vowels revealed that the USH headset has a larger influence on formant production than the UltraFit headset.

Frequency response of the vocal tract considering the glottis opening area during human whistling

AbstractWhistling has become more popular in recent years. “Whistling competitions” are being held in Japan since 2005. However, it can be difficult to teach some people how to whistle. One of the reasons is that theoretical information, including clear descriptions about how to whistle is scant. A better understanding of the principle would be beneficial to both the trainer and the trainee. In this study, the glottis opening area during whistling was measured via endoscopic imaging data. The amplitude characteristics of the vocal tract were determined by measuring the glottis opening area during whistling and calculating the transfer function of the vocal tract in conjunction with that area. By considering the glottis opening area, we could logically explain the fact that, in reality, some notes corresponding to theoretically calculated resonance frequencies did not occur, and we could obtain a calculation result that was close to the physical model. Furthermore, because the calculation result close to the physical model was only associated with certain glottis opening areas, it is evident that not only the shape of the vocal tract and the lip opening area, but also the glottis opening area is an important component of sound production during human whistling.

Deep slow nasal respiration with tight lip closure for immediate attenuation of severe tics

BackgroundSevere intractable tics, which are associated with Tourette syndrome and chronic tic disorder (TS/CTD), severely affect the quality of life. Common less-invasive treatments are often unable to attenuate tics with deep brain stimulation currently being the only effective treatment. We aimed to assess the anti-tic effect of deep slow nasal respiration with tight lip closure using patients with TS/CTD. MethodsWe retrospectively analyzed 10 consecutive patients (9 men, 1 woman; 23–41 years old). We instructed the patients to perform the procedure for 120 s and to obtain a video recording of before and during the procedure. The videos were used to count tics and determine lip competency or incompetency. The counted tics were rated using the modified Rush Video Rating Scale. ResultsCompared with before the procedure, there were significantly lower frequencies of motor and phonic tics, as well as video scored, during the procedure. Eight patients presented with lip incompetency before the procedure and none after the procedure (P = 0.041). There were no side effects associated with the procedure. ConclusionOur findings indicate that deep slow nasal respiration with tight lip closure ameliorates tics in patients with TS/CTD. In accordance with our results, lip opening and oral breathing could be causes of tics, in addition to heritability. Therefore, this novel procedure could improve tics. Furthermore, our findings could contribute toward the development of tic treatments and elucidate their pathophysiology regarding the reward system, hypersensitivity, autonomic nerves, and nasal airway.

Impact of visual and auditory deprivation on speech perception and production in adults

ABSTRACT Speech perception relies on auditory and visual cues and there are strong links between speech perception and production. We aimed to evaluate the role of auditory and visual modalities on speech perception and production in adults with impaired hearing or sight versus those with normal hearing and sight. We examined speech perception and production of three isolated vowels (/i/, /y/, /u/), which were selected based on their different auditory and visual perceptual saliencies, in 12 deaf adults who used one or two cochlear implants (CIs), 14 congenitally blind adults, and 16 adults with normal sight and hearing. The results showed that the deaf adults who used a CI had worse vowel identification and discrimination perception and they also produced vowels that were less typical or precise than other participants. They had different tongue positions in speech production, which possibly partly explains the poorer quality of their spoken vowels. Blind individuals had larger lip openings and smaller lip protrusions for the rounded vowel and unrounded vowels, compared to the other participants, but they still produced vowels that were similar to those produced by the adults with normal sight and hearing. In summary, the deaf adults, even though they used CIs, had greater difficulty in producing accurate vowel targets than the blind adults, whereas the blind adults were still able to produce accurate vowel targets, even though they used different articulatory strategies.

Visual-Tactile Speech Perception and the Autism Quotient.

Multisensory information is integrated asymmetrically in speech perception: An audio signal can follow video by 240ms, but can precede video by only 60ms, without disrupting the sense of synchronicity (Munhall et al., 1996). Similarly, air flow can follow either audio (Gick et al., 2010) or video (Bicevskis et al., 2016) by a much larger margin than it can precede either while remaining perceptually synchronous. These asymmetric windows of integration have been attributed to the physical properties of the signals; light travels faster than sound (Munhall et al., 1996), and sound travels faster than air flow (Gick et al., 2010). Perceptual windows of integration narrow during development (Hillock-Dunn and Wallace, 2012), but remain wider among people with autism (Wallace and Stevenson, 2014). Here we show that, even among neurotypical adult perceivers, visual-tactile windows of integration are wider and flatter the higher the participant’s Autism Quotient (AQ) (Baron-Cohen et al., 2001), a self-report measure of autistic traits. As “pa” is produced with a tiny burst of aspiration (Derrick et al., 2009), we applied light and inaudible air puffs to participants’ necks while they watched silent videos of a person saying “ba” or “pa,” with puffs presented both synchronously and at varying degrees of asynchrony relative to the recorded plosive release burst, which itself is time-aligned to visible lip opening. All syllables seen along with cutaneous air puffs were more likely to be perceived as “pa.” Syllables were perceived as “pa” most often when the air puff occurred 50–100ms after lip opening, with decaying probability as asynchrony increased. Integration was less dependent on time-alignment the higher the participant’s AQ. Perceivers integrate event-relevant tactile information in visual speech perception with greater reliance upon event-related accuracy the more they self-describe as neurotypical, supporting the Happé and Frith (2006) weak coherence account of autism spectrum disorder (ASD).

Computational aeroacoustics to identify sound sources in the generation of sibilant /s/.

A sibilant fricative /s/ is generated when the turbulent jet in the narrow channel between the tongue blade and the hard palate is deflected downwards through the space between the upper and lower incisors and then impinges the space between the lower incisors and the lower lip. The flow eddies in that region become a source of direct aerodynamic sound, which is also diffracted by the speech articulators and radiated outwards. The numerical simulation of these phenomena is complex. The spectrum of an /s/ typically peaks between 4 and 10kHz, which implies that very fine computational meshes are needed to capture the eddies producing such high frequencies. In this work, a large-scale computation of the aeroacoustics of /s/ has been performed for a realistic vocal tract geometry, resorting to two different acoustic analogies. A stabilized finite element method that acts as a large eddy simulation model has been adopted to solve the flow dynamics. Also, a numerical strategy has been implemented that allows the determination, in a single computational run, of the separate contribution of the sound diffracted by the upper incisors from the overall radiated sound. Results are presented for points located close to the lip opening showing the relative influence of the upper teeth depending on frequency.