Speech Communication

Contains research objectives and summary of research.National Institutes of Health (Grant 2 RO1 NS04332-11)National Institutes of Health (Grant 5 RO1 NS04332-11)U. S. Navy Office of Naval Research (Contract ONR N00014-67-A-0204-0069

The quantal larynx: The stable regions of laryngeal biomechanics and implications for speech production

Purpose: Recent proposals suggest that (a) the high dimensionality of speech motor control may be reduced via modular neuromuscular organization that takes advantage of intrinsic biomechanical regions of stability and (b) computational modeling provides a means to study whether and how such modularization works. In this study, the focus is on the larynx, a structure that is fundamental to speech production because of its role in phonation and numerous articulatory functions. Method: A 3-dimensional model of the larynx was created using the ArtiSynth platform (http://www.artisynth.org). This model was used to simulate laryngeal articulatory states, including inspiration, glottal fricative, modal prephonation, plain glottal stop, vocal–ventricular stop, and aryepiglotto– epiglottal stop and fricative. Results: Speech-relevant laryngeal biomechanics is rich with “quantal” or highly stable regions within muscle activation space. Conclusions: Quantal laryngeal biomechanics complement a modular view of speech control and have implications for the articulatory–biomechanical grounding of numerous phonetic and phonological phenomen

A comparison of two methods of formant frequency estimation for high-pitched voices

This study sought to test the accuracy of two methods of formant frequency estimation: artificial laryngeal stimulation via neck placement and via oral tube insertion. Twenty males between the ages of 18 and 45 performed the following three tasks: (1) four seconds of sustained vowel, (2) two seconds of sustained vowel followed by two seconds of artificial laryngeal stimulation via neck placement while ceasing vocal fold vibration and holding structures of the vocal fold filter in a fixed position, and (3) four seconds of sustained vowel, the last two of which were accompanied by artificial laryngeal stimulation via an oral insertion. These tasks were performed on the vowels/a/ and /i/. Four formant frequencies were measured for each task at second one and second three. These measures were compared across second one and second three, as well as across all three tasks. Group means as well as individual subject analysis were compared

Toward a music theater vocal pedagogy for emerging adult female singers

Thesis (D.M.A.)--Boston UniversityThe purpose of this study was to develop a case of contemporary belting pedagogy for emerging adult, female singers. Informants for the case included Jeannette LoVetri and Lisa Popeil, two well-respected pedagogues in both contemporary commercial and classical styles of singing. Data were collected through interviews with the pedagogues and observations of their teaching. The pedagogues' practices confirmed findings from prior research that three facets of singing differentiated contemporary belt singing from classical singing: (a) increased subglottal pressure coupled with increased closed quotient; (b) thyroarytenoid-dominant vocal production; and (c) resonance strategies involving a narrowed pharynx or oral cavity. LoVetri and Popeil characterized pedagogy for emerging adult singers as similar to pedagogy for classical singing in that it ought to be built on breath support and avoidance of vocal fold pressing. Further, the pedagogues recommended utilizing repertoire with moderate demands. However, they emphasized beginning with resonance strategies such as widening the mouth and lowering the velum. To teach emerging adult female singers, vocal music educators must: (a) be able to model appropriate music theater sounds for their students, (b) understand the shows and repertoire of music theater, (c) assign developmentally appropriate music theater literature to individual students; (d) expose students to a variety of musical styles, and (e) impart a functional understanding of voice science related to music theater vocal pedagogy in a way that emerging adult singers can understand. Emerging adult students should commit to performing in a healthy and sustainable way, and voice teachers should be a primary resource for reliable information about vocal health. Beyond this foundational pedagogy, teachers who prepare emerging adults for a career in music theater must ensure that their students receive significant training in acting and dance in addition to singing. Teachers must also help such students gain understanding of the casting process and their own casting strengths. Finally, because music theater is such a challenging industry, teachers should encourage their students to develop skills related to music theater so that they can earn a living, and teachers should highlight the importance of strong emotional, psychological, and financial support systems

Perceptual and acoustic gender differences in the speech of 4 1/2 - 5 1/2 year old children.

The linguistic factors which identify a speaker as being either male or female are reasonably well understood and documented when we are considering adult speakers. Many of these factors become apparent at puberty when the sexes diverge along predictable anatomical and physiological paths. It might be expected, therefore, that prepubertal children should appear relatively undifferentiated in terms of gender and that young boys' and girls' speech should be sexually homogenous. This study has confirmed, however, that adult listeners can correctly identify the sex of a prepubertal child from samples of speech. Results of the present study yielded correct identification rates which varied between 66% (using isolated vowels as the sample) and 76% (using sentences as the sample) - all of these rates were significantly greater than chance. Girls were shown to be better identified by listeners than boys and female listeners tended to be more accurate at identifying gender than male listeners. During the acoustic phase of the study, a number of parameters were selected for measurement which were regarded as likely to be involved in the gender-identification process. Overall, there was a surprisingly large number of negative results, with only a very few parameters yielding significantly sex-different outcomes. No differences were found in Fo between the sexes and only 5 out of 18 comparisons of formant frequency showed significant differences. An investigation into vocal breathiness indicated that, on the basis of this parameter, children could be assigned into perceptual groupings ('most / least male-like') better than into biological sex groupings ('boy / girl'). The conclusion reached is that listeners may use different acoustic cues to identify children's sex from speech than adult's sex, alternatively or additionally, they may be able to focus their perceptive skills more finely on the small acoustic inequalities that exist. The concept of gender-specific speech is discussed in a general commentary of the various influences exerted in the formation of gendered-identities

Singers show enhanced performance and neural representation of vocal imitation

Humans have a remarkable capacity to finely control the muscles of the larynx, via distinct patterns of cortical topography and innervation that may underpin our sophisticated vocal capabilities compared with non-human primates. Here, we investigated the behavioural and neural correlates of laryngeal control, and their relationship to vocal expertise, using an imitation task that required adjustments of larynx musculature during speech. Highly trained human singers and non-singer control participants modulated voice pitch and vocal tract length (VTL) to mimic auditory speech targets, while undergoing real-time anatomical scans of the vocal tract and functional scans of brain activity. Multivariate analyses of speech acoustics, larynx movements and brain activation data were used to quantify vocal modulation behaviour and to search for neural representations of the two modulated vocal parameters during the preparation and execution of speech. We found that singers showed more accurate task-relevant modulations of speech pitch and VTL (i.e. larynx height, as measured with vocal tract MRI) during speech imitation; this was accompanied by stronger representation of VTL within a region of the right somatosensory cortex. Our findings suggest a common neural basis for enhanced vocal control in speech and song. This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part I)’