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This paper reports on the concurrent use of electroglottography (EGG) and electromagnetic articulography (EMA) in the acquisition of EMA trajectory data for running speech. Static and dynamic intersensor distances, standard deviations, and coefficients of variation associated with inter-sample distances were compared in two conditions: with and without EGG present. Results indicate that measurement discrepancies between the two conditions are within the EMA system's measurement uncertainty. Therefore, potential electromagnetic interference from EGG does not seem to cause differences of practical importance on EMA trajectory behaviors, suggesting that simultaneous EMA and EGG data acquisition is a viable laboratory procedure for speech research. [ABSTRACT FROM AUTHOR]

This study evaluates the effects of phrase boundaries on the intra- and intergestural kinematic characteristics of blended gestures, i.e., overlapping gestures produced with a single articulator. The sequences examined are the juncture geminate [d(#)d], the sequence [d(#)z], and, for comparison, the singleton tongue tip gesture in [d(#)b]. This allows the investigation of the process of gestural aggregation [Munhall, K. G., and Löfqvist, A. (1992). “Gestural aggregation in speech: laryngeal gestures,” J. Phonetics 20, 93–110] and the manner in which it is affected by prosodic structure. Juncture geminates are predicted to be affected by prosodic boundaries in the same way as other gestures; that is, they should display prosodic lengthening and lesser overlap across a boundary. Articulatory prosodic lengthening is also investigated using a signal alignment method of the functional data analysis framework [Ramsay, J. O., and Silverman, B. W. (2005). Functional Data Analysis, 2nd ed. (Springer-Verlag, New York)]. This provides the ability to examine a time warping function that characterizes relative timing difference (i.e., lagging or advancing) of a test signal with respect to a given reference, thus offering a way of illuminating local nonlinear deformations at work in prosodic lengthening. These findings are discussed in light of the π-gesture framework of Byrd and Saltzman [(2003) “The elastic phrase: Modeling the dynamics of boundary-adjacent lengthening,” J. Phonetics 31, 149–180]. [ABSTRACT FROM AUTHOR]

Changes in magnitude and variability of duration, fundamental frequency, formant frequencies, and spectral envelope of children's speech are investigated as a function of age and gender using data obtained from 436 children, ages 5 to 17 years, and 56 adults. The results confirm that the reduction in magnitude and within-subject variability of both temporal and spectral acoustic parameters with age is a major trend associated with speech development in normal children. Between ages 9 and 12, both magnitude and variability of segmental durations decrease significantly and rapidly, converging to adult levels around age 12. Within-subject fundamental frequency and formant-frequency variability, however, may reach adult range about 2 or 3 years later. Differentiation of male and female fundamental frequency and formant frequency patterns begins at around age 11, becoming fully established around age 15. During that time period, changes in vowel formant frequencies of male speakers is approximately linear with age, while such a linear trend is less obvious for female speakers. These results support the hypothesis of uniform axial growth of the vocal tract for male speakers. The study also shows evidence for an apparent overshoot in acoustic parameter values, somewhere between ages 13 and 15, before converging to the canonical levels for adults. For instance, teenagers around age 14 differ from adults in that, on average, they show shorter segmental durations and exhibit less within-subject variability in durations, fundamental frequency, and spectral envelope measures. © 1999 Acoustical Society of America. [ABSTRACT FROM AUTHOR]

Speech was recorded from a large number of children ages 5 through 18 years inclusive, at a custom installation at the St. Louis Science Center. Two separate sets of recordings were made: (1) using a high-fidelity microphone, and (2) using one of five telephone handsets. To date, 415 and 456 children have been recorded for each data set, respectively. Microphone recordings are two repetitions of 15 American English vowels in /stop/-V-/stop/ words embedded in a carrier sentence. Five additional English sentences were also recorded twice each. The vocabulary for the telephone recordings included (1) 25 commands (e.g., delete, new name) spoken twice each, (2) six telephone numbers, and (3) spontaneous answers to eight questions. Exact distributions of the number of talkers of each age and sex will be presented. The recording environment, procedures, and real-time digitization equipment will be described and illustrated. [Work supported by Technology Resources, Inc. and Central Institute for the Deaf.] [ABSTRACT FROM AUTHOR]

The use of an opto-electronic sensing device called a 'glossometer' for measurement of tongue position during vowel production has been previously reported [Smith et al, Biomedical Engineering V: Recent Developments, edited by S. Saha (Pergamon, New York, 1986)]. However, while repeatability of this measurement has been well established, its accuracy has not been established due to the lack of an alternative, low-risk technique for comparison. Recently, magnetic resonance (MR) images have been used to obtain vocal tract measurements. [Lakshminarayanan et al., RSNA, Work in Progress-Physics 173(P), 411 (1989)]. In this study, the performance of both systems was evaluated and compared using three custom-made, tongue-palate spacers to hold the tongue steady at three different positions. Distances measured using the two systems were compared with direct measurements of the spacers. It was found that distances measured from the MR images were accurate to within 2 mm in the worst case, but the glossometer demonstrated some distance-dependent error, suggesting a more refined calibration scheme for the glossometer. The experimental procedure and the result will be presented. [ABSTRACT FROM AUTHOR]

Synthesizers based on vocal-tract models do not allow independent control of perceptually relevant characteristics of spectral envelopes. The goal is to develop a tool that will allow assessment of envelope characteristics in speech perception by both normally hearing and hearing-impaired listeners. Using LabVIEW (National Instruments, Inc.), a software synthesizer is being developed that is designed to allow systematic and independent control of these envelope characteristics: (1) the locations of up to five spectral peaks; (2) the locations of the minimums (valleys) between peaks; (3) the peak-to-valley depths in decibels; (4) the ratio of peak-to-valley bandwidths; and (5) the overall spectral shape imposed on the patterns of peaks and valleys. The resulting envelopes specify the component amplitudes of carriers consisting of sinusoids. The phases of the component sinusoids can also be individually specified. Additionally, so-called ''autofunctions'' adjust ''nominal'' values of the envelope variables in accordance with the pattern of peak locations in a manner designed to be consistent with natural speech. For example, a nominal peak-to-valley depth is increased or decreased based on the logarithmic separation between adjacent peaks. Synthetic vowels and the effects of manipulation of the variables will be demonstrated. [ABSTRACT FROM AUTHOR]

Using the autocorrelation method, LPC error signals were computed as differences between the original waves and the predicted waves at each time instant. Analyses of synthesized and human vowel sounds show that the shapes and spectral contents of the instantaneous error signals are almost identical with those of the voice source for synthesized vowel sounds, and that the instants of glottal closure are well defined as maximally negative peaks in the error signals for both kinds of vowel sounds. Time integration of error signals was also performed. For male voices the shapes of integrated and instantaneous error signals are found to be very similar with those of EGG and differentiated EGG signals, respectively. This result supports the possibility that open and closed phases of the vocal folds within each glottal cycle can be determined from such LPC error signals. It was also found that automatic detection of valleys (or peaks) in the integrated error signal may be a robust pitch estimation method for voiced speech segments including synthetic diplophonic sounds. These and other results suggest that these simple LPC error analyses may provide significant information about the voice source. [ABSTRACT FROM AUTHOR]

Sensitivity of formants to perturbations of the location and degree of tongue constriction was studied. These two tongue parameters were extracted from vowel-like midsagittal tongue shapes (N=321) generated using a tongue model [Harshman et al., J. Acoust. Soc. Am. 62, 693-707 (1977)]. The tongue shape data were arranged such that the tongue parameters vary montonically. Lip opening was varied from 0.3 to 6.0 cm2 in 0.3-cm2 steps and the first three formants of each vocal tract were computed. Formant sensitivity was evaluated as dF/dA (Hz/mm), where dA is perturbation in a tongue parameter and dF is the corresponding formant change, and was plotted as a function of the location of tongue constriction. The results can be interpreted in terms of the formant variability, or stability, of a given vocal tract configuration. One finding is that at the tongue position associated with the vowel /u/ the formants are very stable under perturbation of the location of constriction. However, the same position is found to be the most unstable position for both F2 and F3 under perturbation of the degree of constriction. This may explain the largest F2 and F3 variations of /u/ in a set of normalized production data of vowels [Syrdal and Gopal, J. Acoust. Soc. Am. 79, 1086-1100 (1986)]. [Work supported by NIDCD, DC 00296.] [ABSTRACT FROM AUTHOR]

A longstanding tradition in speech research is to correlate articulatory events with acoustic outputs. In this paper, articulatory movements were studied in a two-dimensional modified auditory-perceptual space (MAPS) based on work by Miller [J. Acoust. Soc. Am. 85, 2114-2134 (1989)]. The goal of MAPS was to eliminate z' degeneracy of the original APS. Tongue shapes (n = 1660) were generated by simulating the front- and back-raising gestures described by Ladefoged et al. [J. Acoust. Soc. Am. 64, 1027-1035 (1978)]. Two articulatory parameters (location and degree of constriction) were extracted from the derived tongue shapes and lip opening was varied in 20 steps as another parameter. The F1-F3 frequencies were calculated using a 37-section tube model for the resulting 33 200 vocal tract shapes. The modes of distribution of points in MAPS and formant frequency spaces were compared as a function of articulatory parameters. Differences and similarities between two spaces, and the possibility of describing a direct quantitative relationship between oral gestures and vowel perception, will be discussed. [ABSTRACT FROM AUTHOR]

This study explores one aspect of the articulatory mechanism that underlies emotional speech production, namely, the behavior of linguistically critical and non-critical articulators in the encoding of emotional information. The hypothesis is that the possible larger kinematic variability in the behavior of non-critical articulators enables revealing underlying emotional expression goal more explicitly than that of the critical articulators; the critical articulators are strictly controlled in service of achieving linguistic goals and exhibit smaller kinematic variability. This hypothesis is examined by kinematic analysis of the movements of critical and non-critical speech articulators gathered using eletromagnetic articulography during spoken expressions of five categorical emotions. Analysis results at the level of consonant-vowel-consonant segments reveal that critical articulators for the consonants show more (less) peripheral articulations during production of the consonant-vowel-consonant syllables for high (low) arousal emotions, while non-critical articulators show less sensitive emotional variation of articulatory position to the linguistic gestures. Analysis results at the individual phonetic targets show that overall, between- and within-emotion variability in articulatory positions is larger for non-critical cases than for critical cases. Finally, the results of simulation experiments suggest that the postural variation of non-critical articulators depending on emotion is significantly associated with the controls of critical articulators.

Developmental trends of durational and spectral parameters of five American English diphthongs are investigated by age and gender. Specifically, diphthong durations, the fundamental frequency (F0), and the first three formant (F1, F2, F3) trajectories as well as formant transition rates are analyzed as a function of age, gender and diphthong type. In addition, the distance between diphthong onset and offset positions and those of nearby monophthongs in the formant space is computed and age-dependent trends are presented. Furthermore, a spectral transition mid-point is estimated for a given diphthong trajectory and normalized time durations from onsets to mid-points are analyzed as a function of age and diphthong type. Finally, diphthong classification results using formant-related parameters are reported. Results show the expected age-dependent reductions of diphthong duration, fundamental frequency, onset and offset formant values, and formant transition rate. More interestingly, it is evident that speakers adjust onset and offset positions of diphthongs with respect to monophthongs as a function of age. Normalized duration of the first demisyllable segment is found to be different among diphthongs and that younger children spend more time in the first segment. The implications for diphthong development and the onset-offset definition of diphthongs are discussed in detail.

USC-TIMIT is an extensive database of multimodal speech production data, developed to complement existing resources available to the speech research community and with the intention of being continuously refined and augmented. The database currently includes real-time magnetic resonance imaging data from five male and five female speakers of American English. Electromagnetic articulography data have also been presently collected from four of these speakers. The two modalities were recorded in two independent sessions while the subjects produced the same 460 sentence corpus used previously in the MOCHA-TIMIT database. In both cases the audio signal was recorded and synchronized with the articulatory data. The database and companion software are freely available to the research community.

Acoustic lengthening at prosodic boundaries is well explored, and the articulatory bases for this lengthening are becoming better understood. However, the temporal scope of prosodic boundary effects has not been examined in the articulatory domain. The few acoustic studies examining the distribution of lengthening indicate that boundary effects extend from one to three syllables before the boundary, and that effects diminish as distance from the boundary increases. This diminishment is consistent with the pi-gesture model of prosodic influence [Byrd and Saltzman, J. Phonetics 31, 149-180 (2003)]. The present experiment tests the preboundary and postboundary scope of articulatory lengthening at an intonational phrase boundary. Movement-tracking data are used to evaluate durations of consonant closing and opening movements, acceleration durations, and consonant spatial magnitude. Results indicate that prosodic boundary effects exist locally near the phrase boundary in both directions, diminishing in magnitude more remotely for those subjects who exhibit extended effects. Small postboundary effects that are compensatory in direction are also observed.

An application of functional data analysis (FDA) (Ramsay and Silverman, 2005, Functional Data Analysis, 2nd ed. (Springer-Verlag, New York)) for linguistic experimentation is explored. The functional time-registration method provided by FDA is shown to offer novel advantages in the investigation of articulatory timing. Traditionally, articulatory studies examining the effects of linguistic variables such as prosody on articulatory timing have relied on comparing the durations of speech intervals of interest defined by kinematic landmarks. Such measurements, however, do not preserve information on the detailed, continuous pattern of articulatory timing that unfolds during these intervals. We present an approach that allows the analysis of entire, continuous kinematic trajectories obtained in a movement tracking experiment examining the influence of a phrasal boundary on articulatory patterning. FDA time deformation functions, after alignment of test and reference (control) signals, reveal delaying of articulator movement (i.e., slowing of the internal clock rate) in the presence of a phrase boundary as the speech stream recedes from the boundary. This is a theoretically predicted pattern (Byrd and Saltzman, 2003, The elastic phrase: Modeling the dynamics of boundary-adjacent lengthening, Journal of Phonetics 31, 149-180.), which would be more difficult to validate with a traditional interval-based approach. It is concluded that the FDA time alignment method provides a useful tool for characterizing timing patterns in linguistic experimentation based on continuous kinematic trajectories.

The complexities of how prosodic structure, both at the phrasal and syllable levels, shapes speech production have begun to be illuminated through studies of articulatory behavior. The present study contributes to an understanding of prosodic signatures on articulation by examining the joint effects of phrasal and syllable position on the production of consonants. Articulatory kinematic data were collected for five subjects using electromagnetic articulography (EMA) to record target consonants (labial, labiodental, and tongue tip), located in (1) either syllable final or initial position and (2) either at a phrase edge or phrase medially. Spatial and temporal characteristics of the consonantal constriction formation and release were determined based on kinematic landmarks in the articulator velocity profiles. The results indicate that syllable and phrasal position consistently affect the movement duration; however, effects on displacement were more variable. For most subjects, the boundary-adjacent portions of the movement (constriction release for a preboundary coda and constriction formation for a postboundary onset) are not differentially affected in terms of phrasal lengthening-both lengthen comparably.

Magnetic resonance imaging (MRI) has served as a valuable tool for studying static postures in speech production. Now, recent improvements in temporal resolution are making it possible to examine the dynamics of vocal-tract shaping during fluent speech using MRI. The present study uses spiral k-space acquisitions with a low flip-angle gradient echo pulse sequence on a conventional GE Signa 1.5-T CV/i scanner. This strategy allows for acquisition rates of 8-9 images per second and reconstruction rates of 20-24 images per second, making veridical movies of speech production now possible. Segmental durations, positions, and interarticulator timing can all be quantitatively evaluated. Data show clear real-time movements of the lips, tongue, and velum. Sample movies and data analysis strategies are presented.