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Relative fundamental frequency (RFF) is an acoustic measure that captures the instantaneous changes in fundame nt al frequency (F0) a s a speaker transitions from voicing into and out of [...], Purpose: The effect of phonetic context on relative fundamental frequency (RFF) was examined, in order to develop stimuli sets with minimal within-speaker variability that can be implemented in future clinical protocols. Method: Sixteen speakers with healthy voices produced RFF stimuli. Uniform utterances consisted of 3 repetitions of the same voiced sonorant-voiceless consonant-voiced sonorant speech sequence; moderately variable sentences contained speech sequences with a single voiceless phoneme (/f/, /s/, /∫/, /p/, /t/, or/k/); highly variable sentences were loaded with speech sequences using multiple phonemes. Effects of stimulus type (uniform, moderately variable, and highly variable) and phoneme identity (/f/, /s/, /∫/, /p/, /t/, and /k/) on RFF means and standard deviations were determined. Results: Stimulus type and the interaction of vocal cycle and stimulus type were significant for RFF means and standard deviations but with small effect sizes. Phoneme identity and the interaction of vocal cycle and phoneme identity on RFF means and standard deviations were also significant with small to medium effect sizes. Conclusions: For speakers with healthy voices, uniform utterances with /f/ and /∫/ have the lowest standard deviations and thus are recommended for RFF-based assessments. Future work is necessary to extend these findings to disordered voices. Key Words: voice, speech production, assessment, acoustics

The ability to quantify voice quality precisely and quickly is critical for a number of applications, such as for the clinical assessment of voice disorders as well as automatic detection [...], Purpose: In this experiment, a single comparison stimulus was developed as a reference in a perceptual matching task for the quantification of breathy voice quality. Perceptual judgments of a set of synthetic voice samples were compared to previous data obtained using multiple comparison stimuli 'customized' for different voices (Patel, Shrivastav, & Eddins, 2010). Method: Five male and 5 female samples of the vowel /a/ were selected from the Kay Elemetrics Disordered Voice Database and resynthesized using a Klatt synthesizer. Eleven samples were created for each base voice by manipulating the aspiration noise level. Five samples from each continuum were evaluated in a perceptual matching task in which a single sawtooth and noise comparison stimulus was used to obtain breathiness judgments. Linear regression was used to compare measurements obtained using the new comparison stimulus against the customized comparison stimuli. Results: Results indicated that the noncustomized sawtooth comparison provides reliability and perceptual distances between stimuli similar to those obtained using customized comparison stimuli. Conclusion: A single-variable matching task using a single comparison stimulus can be used to obtain perceptual estimates of breathiness across voices and experiments in a laboratory setting. This technique will help develop models of voice-quality perception. Key Words: voice quality, matching, breathy, single-variable

Stop consonants are produced by temporarily occluding the vocal tract at a specific location along its length. The ability of a talker to grade the shape, degree, and timing of [...], Purpose: The present study was designed to investigate the relation of formant transitions to place-of-articulation for stop consonants. A speech production model was used to generate simulated utterances containing voiced stop consonants, and a perceptual experiment was performed to test their identification by listeners. Method: Based on a model of the vocal tract shape, a theoretical basis for reducing highly variable formant transitions to more invariant formant deflection patterns as a function of constriction location was proposed. A speech production model was used to simulate vowel-consonant-vowel (VCV) utterances for 3 underlying vowel-vowel contexts and for which the constriction location was incrementally moved from the lips toward the velar part of the vocal tract. These simulated VCVs were presented to listeners who were asked to identify the consonant. Results: Listener responses indicated that phonetic boundaries were well aligned with points along the vocal tract length where there was a shift in the deflection polarity of either the 2nd or 3rd formant. Conclusions: This study demonstrated that regions of the vocal tract exist that, when constricted, shift the formant frequencies in a predictable direction. Based on a perceptual experiment, the boundaries of these acoustically defined regions were shown to coincide with phonetic categories for stop consonants. KEY WORDS: vocal tract shape, consonant identification, formant transitions

Purpose: Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas. Method: Forty-eight young adult, middle-aged, and old Fischer 344/Brown Norway rats received 8 weeks of tongue exercise. Protrusive tongue forces were measured before and after exercise. GG muscle fiber cross-sectional area was measured in exercised rats and was compared with cross-sectional areas in a no-exercise control group. Results: A significant increase in maximum tongue force was found following exercise in all age groups. In addition, a trend for increased GG muscle fiber cross-sectional area and a significant increase in variability of GG muscle fiber cross-sectional area was identified postexercise. Conclusion: The findings of this study have implications for treatment of elderly persons with dysphagia using tongue exercise programs. Specifically, increases in tongue force that occur following 8 weeks of progressive resistance tongue exercise may be accompanied by alterations in tongue muscle fiber morphology. These changes may provide greater strength and endurance for goal-oriented actions associated with the oropharyngeal swallow and should be investigated in future research. KEY WORDS: tongue, aging, rat, tongue exercise, genioglossus, swallowing, Deglutition, Sarcopenia, the age-related loss of skeletal muscle mass, strength, and function (Rosenberg, 1997) is caused by multiple factors (Doherty, 2003). A major component of sarcopenia is muscle atrophy, which is [...]

Purpose: This article integrates published acoustic data on the development of vowel production. Age specific data on formant frequencies are considered in the light of information on the development of [...]

Inferences were made regarding vocal tract vowel space during fluently produced utterances through examination of the first two formant frequencies. Fifteen adult males served as subjects, representing separate groups of untreated and treated individuals who stutter and nonstuttering controls. The steady-state portion of formant one (F1) and formant two (F2) was examined in the production of various CVC tokens containing the vowels /i/, /u/, and /a/. Vocal tract vowel space was estimated three ways. The first analysis scheme involved measurement of formant frequency spacing. The second measure involved calculating the area of the vowel space triangle. The third measure was based on calculating the average Euclidean distance from each subject's midpoint "centroid" vocal tract position to the corresponding /i/, /u/, and /a/ points on the vowel triangle. The formant frequency spacing measures proved to be most revealing of group differences, with the untreated stutterers showing significantly greater vowel centralization than the treated group and control group. Discussion focuses on the vocal tract articulation characterizing fluent speech productions and possible treatment implications for persons who stutter. KEY WORDS: stuttering, fluency, acoustics, formant frequency, vowel centralization