Acoustic Properties Of Speech Research Articles

Avaliação do processamento auditivo de sons não-verbais em indivíduos com doença de Parkinson

Entendemos que o processamento auditivo é o processo de como o indivíduo gerencia as informações recebidas auditivamente. É reconhecida a importância da percepção auditiva de seqüências e padrões temporais de sons na aquisição e compreensão dos componentes simbólicos da linguagem, sendo que as propriedades acústicas da fala poderiam ser reduzidas aos componentes básicos de duração e freqüência. Entre os eventos que percebemos por meio da audição, a fala é o mais importante, sendo que esta pode apresentar-se alterada na Doença de Parkinson. OBJETIVO: Avaliar o desempenho de portadores de doença de Parkinson nos Testes de Padrão de Freqüência e de Duração. FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Avaliou-se a identificação de estímulos sonoros não-verbais, por meio de três tipos de respostas: humming, nomeação e apontar. Os estímulos eram constituídos por dez seqüências de três e quatro sons, variando em freqüência e duração. RESULTADOS: Mostraram-se que não houve diferença quanto ao tipo de resposta; houve um melhor desempenho utilizando o parâmetro três estímulos em oposição a quatro e o aspecto da duração em oposição ao de freqüência. Ressalta-se ainda que o desempenho da população avaliada foi inferior aos indivíduos normais. CONCLUSÃO: A capacidade de ordenação temporal de sons é uma importante função do sistema auditivo nervoso central. Essa habilidade permite que o ouvinte faça discriminações baseadas na ordenação ou seqüenciação de estímulos auditivos. Sendo assim, a contribuição desse estudo é significativa, uma vez que inicia a reflexão do processo de análise e interpretação de sons pelos indivíduos com doença de Parkinson.

Acoustical properties of speech as indicators of depression and suicidal risk.

Acoustic properties of speech have previously been identified as possible cues to depression, and there is evidence that certain vocal parameters may be used further to objectively discriminate between depressed and suicidal speech. Studies were performed to analyze and compare the speech acoustics of separate male and female samples comprised of normal individuals and individuals carrying diagnoses of depression and high-risk, near-term suicidality. The female sample consisted of ten control subjects, 17 dysthymic patients, and 21 major depressed patients. The male sample contained 24 control subjects, 21 major depressed patients, and 22 high-risk suicidal patients. Acoustic analyses of voice fundamental frequency (Fo), amplitude modulation (AM), formants, and power distribution were performed on speech samples extracted from audio recordings collected from the sample members. Multivariate feature and discriminant analyses were performed on feature vectors representing the members of the control and disordered classes. Features derived from the formant and power spectral density measurements were found to be the best discriminators of class membership in both the male and female studies. AM features emerged as strong class discriminators of the male classes. Features describing Fo were generally ineffective discriminators in both studies. The results support theories that identify psychomotor disturbances as central elements in depression and suicidality.

Some acoustic effects of speaking style on utterances for automatic speaker verification

This paper reports the results of an experiment on the effects of six speaking styles on some of the acoustic properties of speech. The experiment was part of an exploration of within-speaker variation in connection with automatic speaker verification (ASV), pursuing the hypothesis that the elicitation of style variation in the training phase of an ASV system (‘structured training’) would enhance the performance of the system. Swedish-speaking subjects produced a digit sequence at varying speaking rates and loudness levels, and also with simulated denasality (pinched nose) and under cognitive stress. Duration of vowels and consonants, and formant frequencies of vowels, were measured. A number of consistent patterns of variation emerged for duration and vowel quality and are reported here. The discussion explores the relation between the patterns observed and the success, or in the case of speech under stress the failure, of structured training in reducing the error rates in ASV.

Perceiving the sex and identity of a talker without natural vocal timbre.

The personal attributes of a talker perceived via acoustic properties of speech are commonly considered to be an extralinguistic message of an utterance. Accordingly, accounts of the perception of talker attributes have emphasized a causal role of aspects of the fundamental frequency and coarse-grain acoustic spectra distinct from the detailed acoustic correlates of phonemes. In testing this view, in four experiments, we estimated the ability of listeners to ascertain the sex or the identity of 5 male and 5 female talkers from sinusoidal replicas of natural utterances, which lack fundamental frequency and natural vocal spectra. Given such radically reduced signals, listeners appeared to identify a talker's sex according to the central spectral tendencies of the sinusoidal constituents. Under acoustic conditions that prevented listeners from determining the sex of a talker, individual identification from sinewave signals was often successful. These results reveal that the perception of a talker's sex and identity are not contingent and that fine-grain aspects of a talker's phonetic production can elicit individual identification under conditions that block the perception of voice quality.

Vocal Expression of Emotion: Acoustic Properties of Speech Are Associated With Emotional Intensity and Context

Acoustic properties of speech likely provide external cues about internal emotional processes, a phenomenon called vocal expression of emotion Testing this supposition, we examined fundamental frequency (F0) and two perturbation measures, jitter and shimmer, in short speech samples recorded from subjects performing a lexical decision task Statistically significant differences were found between baseline and on-task values and as interaction effects involving differences in trait levels of emotional intensity and the proportion of success versus failure feedback received These results indicate that acoustic properties of speech can be used to index emotional processes and that characteristic differences in emotional intensity may mediate vocal expression of emotion

Anatomic development of the vocal tract: Implications for speech motor control and acoustic properties of speech

It has been proposed that models of speech production should be developed with consideration of age and gender differences. Although some important age differences in anatomy and acoustic patterns of vocalization have been described between infants and adults, much less attention has been given to the anatomic development of the speech production system between infancy and adulthood. This talk reviews the anatomic development of the craniofacial, oral, and laryngeal systems of speech production between birth and young adulthood. Implications of the developmental patterns are considered for the ontogeny of speech production, especially speech motor control and acoustic patterns of speech. Consideration also is given to gender and race as they relate to vocal tract anatomy and its development in children. Topics to be reviewed include: craniofacial skeleton, nasopharynx, tongue, lips, and larynx. The overall pattern of development will be summarized for each system and intervals of especially rapid growth will be identified. A major hypothesis to be evaluated is whether growth is harmonious across the major anatomic systems.

Talker continuity and the use of rate information during phonetic perception.

Research has shown that speaking rate provides an important context for the perception of certain acoustic properties of speech. For example, syllable duration, which varies as a function of speaking rate, has been shown to influence the perception of voice onset time (VOT) for syllable-initial stop consonants. The purpose of the present experiments was to examine the influence of syllable duration when the initial portion of the syllable was produced by one talker and the remainder of the syllable was produced by a different talker. A short-duration and a long-duration /bi/-/pi/ continuum were synthesized with pitch and formant values appropriate to a female talker. When presented to listeners for identification, these stimuli demonstrated the typical effect of syllable duration on the voicing boundary: a shorter VOT boundary for the short stimuli than for the long stimuli. An /i/ vowel, synthesized with pitch and formant values appropriate to a male talker, was added to the end of each of the short tokens, producing a new hybrid continuum. Although the overall syllable duration of the hybrid stimuli equaled the original long stimuli, they produced a VOT boundary similar to that for the short stimuli. In a second experiment, two new /i/ vowels were synthesized. One had a pitch appropriate to a female talker with formant values appropriate to a male talker; the other had a pitch appropriate to a male talker and formants appropriate to a female talker. These vowels were used to create two new hybrid continua. In a third experiment, new hybrid continua were created by using more extreme male formant values. The results of both experiments demonstrated that the hybrid tokens with a change in pitch acted like the short stimuli, whereas the tokens with a change in formants acted like the long stimuli. A fourth experiment demonstrated that listeners could hear a change in talker with both sets of hybrid tokens. These results indicate that continuity of pitch but not formant structure appears to be the critical factor in the calculation of speaking rate within a syllable.

The acoustical analysis of children's use of prosody in assertive and directive contexts

Prosodic features of children's utterances were compared across asser tive directive tasks, in order to determine how these acoustical proper ties of speech are used for communication. Methodological difficulties inherent in many previous investigations were averted by using a procedure that ensured that prosody was judged independently of communicative purpose. Four children aged 1;11 were audiotaped while in contexts designed to elicit assertive or directive utterances to an adult. The children's utterances were analysed for intensity and duration as well as beginning, end, peak, and low frequencies, fre quency range, and contour changes. Results showed that in the direc tive context intensity was increased overall. Increased end point fre quency and a trend for increased overall peak frequency were also noted, although the way in which the latter features were used varied with individual children. Beginning frequency and frequency range also showed significant task by child interactions, but no main effect for task. These findings indicate that children at this age use prosodic elements of speech differentially across communicative contexts and code their intentions with multiple features. Differences between chil dren may reflect individual differences or developmental effects.

The use of rate information during phonetic perception depends on pitch continuity

Studies have demonstrated that speaking rate provides an important context for the perception of certain acoustic properties of speech. For example, syllable duration, which varies as a function of speaking rate, has been shown to influence the perception of voice‐onset‐time (VOT) for syllable‐initial stop consonants. The purpose of the present experiments was to examine the influence of syllable duration when the initial portion of the syllable was produced by one talker, and the remainder of the syllable was produced by a different talker. A short duration and a long duration /bi‐pi/ continuum was synthesized with pitch and formant values appropriate to a female talker. When presented to listeners for identification, these stimuli demonstrated the typical effect of syllable duration on the voicing boundary: a shorter VOT boundary for the short stimuli relative to the long. An /i/ vowel, synthesized with pitch and formant values appropriate to a male talker, was added to the end of each of the short tokens producing a new “hybrid” continuum. Although the overall syllable durations of the hybrid stimuli equaled the original long stimuli, they produced a VOT boundary similar to the short stimuli. In a follow‐up experiment, two new /i/ vowels were synthesized. One had a pitch appropriate to a female talker with formant values appropriate to a male talker, while the second had a pitch appropriate to a male talker and formants appropriate to a female talker. These vowels were used to create two new hybrid continua. The results of this second experiment indicated that continuity of pitch but not of formant structure appears to be the important factor in the integration of speaking rate within a syllable. [Work supported by NIH.]