Spoken Vowels Research Articles

The pupil dilation response as an indicator of visual cue uncertainty and auditory outcome surprise.

In everyday perception, we combine incoming sensory information with prior expectations. Expectations can be induced by cues that indicate the probability of following sensory events. The information provided by cues may differ and hence lead to different levels of uncertainty about which event will follow. In this experiment, we employed pupillometry to investigate whether the pupil dilation response to visual cues varies depending on the level of cue-associated uncertainty about a following auditory outcome. Also, we tested whether the pupil dilation response reflects the amount of surprise about the subsequently presented auditory stimulus. In each trial, participants were presented with a visual cue (face image) which was followed by an auditory outcome (spoken vowel). After the face cue, participants had to indicate by keypress which of three auditory vowels they expected to hear next. We manipulated the cue-associated uncertainty by varying the probabilistic cue-outcome contingencies: One face was most likely followed by one specific vowel (low cue uncertainty), another face was equally likely followed by either of two vowels (intermediate cue uncertainty) and the third face was followed by all three vowels (high cue uncertainty). Our results suggest that pupil dilation in response to task-relevant cues depends on the associated uncertainty, but only for large differences in the cue-associated uncertainty. Additionally, in response to the auditory outcomes, the pupil dilation scaled negatively with the cue-dependent probabilities, likely signalling the amount of surprise.

Corollary discharge function in healthy controls: Evidence about self-speech and external speech processing.

As we speak, corollary discharge mechanisms suppress the auditory conscious perception of the self-generated voice in healthy subjects. This suppression has been associated with the attenuation of the auditory N1 component. To analyse this corollary discharge phenomenon (agency and ownership), we registered the event-related potentials of 42 healthy subjects. The N1 and P2 components were elicited by spoken vowels (talk condition; agency), by played-back vowels recorded with their own voice (listen-self condition; ownership) and by played-back vowels recorded with an external voice (listen-other condition). The N1 amplitude elicited by the talk condition was smaller compared with the listen-self and listen-other conditions. There were no amplitude differences in N1 between listen-self and listen-other conditions. The P2 component did not show differences between conditions. Additionally, a peak latency analysis of N1 and P2 components between the three conditions showed no differences. These findings corroborate previous results showing that the corollary discharge mechanisms dampen sensory responses to self-generated speech (agency experience) and provide new neurophysiological evidence about the similarities in the processing of played-back vowels with our own voice (ownership experience) and with an external voice.

Real-time magnetic resonance imaging reveals distinct vocal tract configurations during spontaneous and volitional laughter.

A substantial body of acoustic and behavioural evidence points to the existence of two broad categories of laughter in humans: spontaneous laughter that is emotionally genuine and somewhat involuntary, and volitional laughter that is produced on demand. In this study, we tested the hypothesis that these are also physiologically distinct vocalizations, by measuring and comparing them using real-time magnetic resonance imaging (rtMRI) of the vocal tract. Following Ruch and Ekman (Ruch and Ekman 2001 In Emotions, qualia, and consciousness (ed. A Kaszniak), pp. 426-443), we further predicted that spontaneous laughter should be relatively less speech-like (i.e. less articulate) than volitional laughter. We collected rtMRI data from five adult human participants during spontaneous laughter, volitional laughter and spoken vowels. We report distinguishable vocal tract shapes during the vocalic portions of these three vocalization types, where volitional laughs were intermediate between spontaneous laughs and vowels. Inspection of local features within the vocal tract across the different vocalization types offers some additional support for Ruch and Ekman's predictions. We discuss our findings in light of a dual pathway hypothesis for the neural control of human volitional and spontaneous vocal behaviours, identifying tongue shape and velum lowering as potential biomarkers of spontaneous laughter to be investigated in future research. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

The Method of the Main Tone Detection in the Structure of Electromyographic Signals for the Task of Broken Human Communicative Function Compensation

In the work the method of electromyographic signals processing for the task of broken human communicative function compensation is developed. The method allows to detect the signs of main tone in the structure of electromyographic signals, that were recorded from the surface of patients neck near the vocal folds. Using this signs it is possible to identify the mentally spoken vowel and vocalised consonant phonemes and to identify the speech of patients with broken or lost communicative function. The developed method includes two stages, namely: preparatory and basic. The purpose of the preparatory stage is to obtain data on the individual features of the patient's speach, in particular the approximate value of the main tone frequency and the frequency interval of the main tone frequency when patient is trying to utter test sequences of sounds at certain points in time. These data are necessary to enable the use of the basic stage of the method, which involves the processing of electromyographic signals recorded in an arbitrary attempt to pronounce arbitrary sounds, words or phrases by the patient. It is proposed to processing the electromyographic signals by methods of spectral-correlation analysis using the sliding window method if presenting of such biosignals in the form of a piecewise stationary random process to detect the time intervals of the presence of main tone signs. Within each sliding window the estimates of the power spectral density distribution are calculated and averaged over the frequency and power within the predetermined interval of existence of the main tone frequency. The obtained averaged estimates make it possible to set the time intervals of the main tone presence and, accordingly, the subsequent identification of vowel and consonant vocalised phonemes. The experimentally registered EMG signal was processed by the developed method with different values of the sliding window width.

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.

P6539Automated detection of atrial fibrillationb based on vocal features analysis

Abstract Background Early identification of atrial fibrillation (AF) has been a long-standing clinical challenge and an unmet need. AF may be present without the patient being aware of any symptoms, leading to a delay in or failure of diagnosis. ESC guidelines recommend opportunistically screening patients >65 years of age using pulse palpation or an ECG rhythm strip, however these methods have limited effectivity. Analysis of natural speech signals has been used as a monitoring tool for various medical conditions and has recently been reported to enable estimation of heart rate. In this study we evaluated the efficacy of vocal features analysis in the detection of AF and in discriminating between sinus rhythm (SR) and episodes of AF. Methods In this prospective multicenter study, patients with persistent AF admitted for cardioversion were enrolled. A total of 86 patients in 2 centers were included. Prior to cardioversion, the patients spoke specific vowels and words according to a pre-specified protocol; an ECG tracing was simultaneously recorded. Following successful cardioversion and recovery from sedation, these recordings were repeated in SR. The recordings of the first 34 patients were used to develop an algorithm of AF detection based on analysis of acoustic features in SR and AF conditions. The algorithm was then validated in all of the patients (n=86) in the following manner: 25% of SR recordings were used to train the algorithm while the remaining 75% of SR and 100% of AF data from every patient were tested with the algorithm to distinguish between AF and SR. Results A total of 513 recordings from 86 patients were analyzed. Classification of the recordings as AF or SR was performed using varying cutoff values of the separation parameter. The resulting curve showing the specificity and sensitivity of the developed algorithm for distinguishing AF from SR is presented. Two specific examples of working points are a specificity of 92% and sensitivity of 83%, and a specificity of 82% and sensitivity of 92%. Conclusions This study demonstrates the feasibility of detecting AF and discriminating it from SR using analysis of acoustic features extracted from spoken vowels. The potential use of this method for wider population screening should be further evaluated.

Detecting Foreign Accents in Song

This paper presents three experiments exploring the perception and production of accents in song. In a perception experiment, participants listened to passages sung and spoken by native and non-native speakers of English. The participants did better at identifying native speakers when listening to the spoken passages. Accents were also judged as more native-like in song than in speech. In addition, two production experiments compared the acoustic characteristics (pitch, duration, F1 and F2) of sung and spoken vowels, produced by native and non-native speakers of English. Both native and non-native speakers changed the pitch and duration of their vowels when singing; the vowel quality was not consistently shifted. Together, the results indicate that the melody imposed by the song impacts the suprasegmental properties of pronunciation whereas the segmental properties remain largely intact. Based on these results, we conclude that a main reason why accents are more difficult to detect in song than in speech is that the rhythm and melody imposed by the song mask intonational cues to accent.

Decoding Speech With Integrated Hybrid Signals Recorded From the Human Ventral Motor Cortex.

Restoration of speech communication for locked-in patients by means of brain computer interfaces (BCIs) is currently an important area of active research. Among the neural signals obtained from intracranial recordings, single/multi-unit activity (SUA/MUA), local field potential (LFP), and electrocorticography (ECoG) are good candidates for an input signal for BCIs. However, the question of which signal or which combination of the three signal modalities is best suited for decoding speech production remains unverified. In order to record SUA, LFP, and ECoG simultaneously from a highly localized area of human ventral sensorimotor cortex (vSMC), we fabricated an electrode the size of which was 7 by 13 mm containing sparsely arranged microneedle and conventional macro contacts. We determined which signal modality is the most capable of decoding speech production, and tested if the combination of these signals could improve the decoding accuracy of spoken phonemes. Feature vectors were constructed from spike frequency obtained from SUAs and event-related spectral perturbation derived from ECoG and LFP signals, then input to the decoder. The results showed that the decoding accuracy for five spoken vowels was highest when features from multiple signals were combined and optimized for each subject, and reached 59% when averaged across all six subjects. This result suggests that multi-scale signals convey complementary information for speech articulation. The current study demonstrated that simultaneous recording of multi-scale neuronal activities could raise decoding accuracy even though the recording area is limited to a small portion of cortex, which is advantageous for future implementation of speech-assisting BCIs.

Acoustic and kinematic analyses of Mandarin vowels in speakers with hearing impairment

ABSTRACTThe central aim of this experiment was to compare acoustic parameters, formant frequencies and vowel space area (VSA), in adolescents with hearing-impaired (HI) and their normal-hearing (NH) peers; for kinematic parameters, the movements of vocal organs, especially the lips, jaw and tongue, during vowel production were analysed. The participants were 12 adolescents with different degrees of hearing impairment. The control group consisted of 12 age-matched NH adolescents. All participants were native Chinese speakers who were asked to produce the Mandarin vowels /a/, /i/ and /u/, with subsequent acoustic and kinematic analysis. There was significant difference between the two groups. Additionally, the HI group produced more exaggerated mouth and less tongue movements in all vowels, compared to their NH peers. Results were discussed regarding possible relationship between acoustic data, articulatory movements and degree of hearing loss to provide an integrative assessment of acoustic and kinematic characteristics of individuals with hearing loss.

DOMINANCE, PROFICIENCY, AND SPANISH HERITAGE SPEAKERS’ PRODUCTION OF ENGLISH AND SPANISH VOWELS

AbstractThis study examines how dominance and proficiency relate to Spanish heritage speaker vowel productions. Participants’ normalized vowel measurements were compared to nonheritage native speakers of Spanish and English using the Pillai score, an output of Multivariate Analysis of Variances (MANOVAs) that allows comparisons across distributions of two or more dependent variables. With Pillai scores as the dependent variable, we created two multiple regression models for each language, one with factors related to dominance, one with factors related to proficiency. We use commonality analysis (variance partitioning) to determine the unique and shared contribution of each variable to the regression models. The results showed different patterns of unique and shared variance across English and Spanish for the factors related to dominance and also for proficiency. Given this, we maintain that it is important to preserve dominance and proficiency as separate but related constructs when considering heritage speaker linguistic data.

Acoustic Characteristics of Fricatives /s/ and /∫/ Produced by Speakers with Parkinson's Disease.

PurposeThis study investigated acoustic characteristics of fricatives produced in a repeated syllables task by speakers with Parkinson’s disease (PD), focusing on temporal, intensity, and spectral moment analyses.MethodsTen participants with PD and nine neurologically-healthy participants were asked to repeat the two words, sigh and shy, ten times in a row and at a comfortable rate. Acoustic measurements were made for duration and intensity of each fricative and vowel, plus four coefficients of spectral moments for the fricatives.ResultsResults indicated a varying effect of duration difference between group, with marginally shorter duration of fricatives but much shorter duration of vowels in speakers with PD, as compared to controls; comparable vowel-fricative intensity differences for the two groups; and for the group with PD relatively intact coarticulation throughout fricative.ConclusionsThe findings suggest considering the complex effect of overall speech rate on different kinds of segments in PD. The findings also have implications for speech stimuli in research on coarticulation.

Positive emotion impedes emotional but not cognitive conflict processing

Cognitive control enables successful goal-directed behavior by resolving a conflict between opposing action tendencies, while emotional control arises as a consequence of emotional conflict processing such as in irony. While negative emotion facilitates both cognitive and emotional conflict processing, it is unclear how emotional conflict processing is affected by positive emotion (e.g., humor). In 2 EEG experiments, we investigated the role of positive audiovisual target stimuli in cognitive and emotional conflict processing. Participants categorized either spoken vowels (cognitive task) or their emotional valence (emotional task) and ignored the visual stimulus dimension. Behaviorally, a positive target showed no influence on cognitive conflict processing, but impeded emotional conflict processing. In the emotional task, response time conflict costs were higher for positive than for neutral targets. In the EEG, we observed an interaction of emotion by congruence in the P200 and N200 ERP components in emotional but not in cognitive conflict processing. In the emotional conflict task, the P200 and N200 conflict effect was larger for emotional than neutral targets. Thus, our results show that emotion affects conflict processing differently as a function of conflict type and emotional valence. This suggests that there are conflict- and valence-specific mechanisms modulating executive control.

Phonetic Sources of Sound Change: The Influence of Thai on Nasality in Pwo Karen

The phonetic realization of nasal vowels produced by Pwo speakers of different ages can vary. The present study investigated mid and low nasal vowels of Pwo speakers from Mae Hong Son province, Thailand. Due to the higher tendency of language contact with Thai, the younger group’s nasal vowels were expected to lose more nasality than the older group. The emergence of final nasal consonants was also expected in the younger group. The nasalization duration and consonant duration of both groups were analyzed. The results showed that, regardless of age, mid nasal vowels of some speakers had final nasal consonants, while low nasal vowels of all speakers did not. Furthermore, the older group had both longer nasalization duration and consonant duration than the younger group, suggesting their higher tendency to preserve nasality. The younger group had shorter nasalization duration and consonant duration, indicating the loss of nasality in vowels without compensatory final nasal consonants. The change might be due to the vowel quality. High vowels were fully denasalized with no compensatory final nasal consonants. Mid vowels were nasalized with the emergence of final nasal consonants. Low vowels remained nasalized without final nasal consonants. We could not confirm that the emergence of final nasal consonants was induced by Thai because it occurred in both groups. The existence of final nasal consonants in the younger group could not be used as evidence of an effect of contact.

Self-Reported Symptoms of Depression and PTSD Are Associated with Reduced Vowel Space in Screening Interviews

Reduced frequency range in vowel production is a well documented speech characteristic of individuals with psychological and neurological disorders. Affective disorders such as depression and post-traumatic stress disorder (PTSD) are known to influence motor control and in particular speech production. The assessment and documentation of reduced vowel space and reduced expressivity often either rely on subjective assessments or on analysis of speech under constrained laboratory conditions (e.g. sustained vowel production, reading tasks). These constraints render the analysis of such measures expensive and impractical. Within this work, we investigate an automatic unsupervised machine learning based approach to assess a speaker's vowel space. Our experiments are based on recordings of 253 individuals. Symptoms of depression and PTSD are assessed using standard self-assessment questionnaires and their cut-off scores. The experiments show a significantly reduced vowel space in subjects that scored positively on the questionnaires. We show the measure's statistical robustness against varying demographics of individuals and articulation rate. The reduced vowel space for subjects with symptoms of depression can be explained by the common condition of psychomotor retardation influencing articulation and motor control. These findings could potentially support treatment of affective disorders, like depression and PTSD in the future.

The influence of sung vowels on pitch perception

Phonologists have demonstrated that in speech there is an intrinsic pitch of vowels, i.e., that different pitch heights are perceived for different spoken vowels with the same mean fundamental frequency. Only limited work has been done on the impact of sung vowels on perceived pitch and previous studies, using forced choice paradigms, have found conflicting results comparing Front/Close to Back/Open vowels: Ternstrom, Sundberg, and Collden (1988), using manipulated sung tones, found that Front/Close vowels were perceived as higher than other vowels while Fowler and Brown (1997), using synthesized tones, found that Front/Close was perceived lower than Back/Open. The current study uses a method-of-adjustment paradigm to examine pitch perception of all four extremal vowels: Front/Close (/i/), Front/Open (/ae/), Back/Close (/u/), and Back/Open (/ɑ/), using completely controlled, but realistic synthesis. It also assesses whether different models of pitch perception are necessary for the various vowel types. In the experiment, the subjects are asked to match a reference tone that has no formants against a stimulus tone with first and second formants corresponding to a particular vowel. Both the reference and stimulus tones are identical in their synthesis except for the formants and are 300 ms in length.

Perception of acoustically similar vowels from English and Hebrew

The formant theory suggests that vowels are differentiated perceptually based on the presence of concentrated bands of harmonic energy in the vowel's acoustical signal. Vowels from different languages often contain formants with similar configurations, but it is unclear what effect cross-language variations have on the perception of the vowels. This study was completed to find when English-speaking listeners are able to differentiate between vowels spoken in two languages, General American English and Modern Hebrew. Natural vowels in kVp syllables were recorded and acoustically normalized using the Bark scale. The English and Hebrew vowels were paired in test groups based on the normalized formant values and the fundamental frequencies of the speakers. Listeners designated each pair as “same” or “different.” It was hypothesized that listeners were more likely to differentiate between the vowels in English-Hebrew pairs than in same-language pairs, and that they were more likely to differentiate between vowels with higher Bark scale differences. However, Bark scale differences did not always match perceived differences. Listeners demonstrated the least difficulty discriminating between different-language pairs containing /e/ and /o/ (60–90% accuracy), more difficulty for English /ɑ/ and Hebrew /a/ (40–80% accuracy), and the most difficulty for /i/ and /u/ (10–60% accuracy).

What Does Motor Efference Copy Represent? Evidence from Speech Production

How precisely does the brain predict the sensory consequences of our actions? Efference copy is thought to reflect the predicted sensation of self-produced motor acts, such as the auditory feedback heard while speaking. Here, we use magnetoencephalographic imaging (MEG-I) in human speakers to demonstrate that efference copy prediction does not track movement variability across repetitions of the same motor task. Specifically, spoken vowels were less accurately predicted when they were less similar to a speaker's median production, even though the prediction is thought to be based on the very motor commands that generate each vowel. Auditory cortical responses to less prototypical speech productions were less suppressed, resembling responses to speech errors, and were correlated with later corrective movement, suggesting that the suppression may be functionally significant for error correction. The failure of the motor system to accurately predict less prototypical speech productions suggests that the efferent-driven suppression does not reflect a sensory prediction, but a sensory goal.

Alterations in speech and voice in patients with mucopolysaccharidoses

The mucopolysaccharidoses are a group of lysosomal disorders characterized by abnormal accumulation of glycosaminoglycans within cell lysosomes leading to a variety of signs and symptoms including alterations in speech and voice production. These changes were analysed in 44 patients with mucopolysaccharidosis (MPS) types I, II, and VI using standardized protocols. Compared to healthy individuals the diadochokinetic rate for the fast repetition of syllables was slower and more irregular, the voice-onset time for the voiceless consonant /p/ was shorter, and most patients had a hoarse voice. The fundamental frequency (F0) of sustained spoken vowels was in the normal range for most women and children with MPS, but adult males with MPS had a higher F0 than healthy men.

The Discrimination of English Vowels by Cantonese ESL Learners in Hong Kong: A Test of the Perceptual Assimilation Model

This article discusses the results of a study which investigated Cantonese ESL learners’ perception of English vowels and their perceived similarity between similar L1 and L2 vowels in an attempt to test the prediction of the Perceptual Assimilation Model (PAM). Forty university English majors participated in three L2 perception tasks, which aimed at discerning their perception of English vowels spoken in different contexts, and one L1 L2 speech perception task, which aimed at discerning their classification of L2 vowels into native vowel categories and their perceived similarity between similar L1 and L2 vowels. It was found that their classifications of English vowels into Cantonese vowels and their perception of the corresponding English vowels did not provide strong support for the prediction of the model. The effects and extent of native language phonological influence are yet to be determined.

Infants' ability to separate superimposed vowels

Three- and seven-month-old infants were tested using an observer-based procedure in three tasks to assess sound source segregation and selective attention. The stimuli were tokens of the vowels /a/ and /i/, spoken by two male talkers, 519 ms in duration, presented at 70 dB SPL. Success was defined as achieving 80% correct in fewer than 40 test trials. In the first task, infants heard one vowel spoken by one talker repeated at 1319 ms intervals. They learned to respond when the talker changed on one repetition of the vowel. In the second task, the tokens of the two talkers producing the same vowel were superimposed. Infants heard combined tokens repeatedly and learned to respond when the vowel produced by one talker changed. In the third task, either talker could produce the changed vowel. Infants learned to respond when one talker, but not the other, produced the changed vowel. Nearly all infants succeeded in the first two tasks. Nearly all 7-month-olds, but few 3-month-olds succeeded at the third task. These results suggest that the ability to selectively attend to one of two easily discriminable voices matures after the ability to segregate those voices. [Work supported by R01DC00396 and P30DC04661.]