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Objective: To investigate aerodynamic and laryngeal factors associated with place-dependent voice onset time (VOT) differences. Methods: The speech materials were /pΛ, tΛ, kΛ/, each produced 15 times by 10 adult English speakers in the carrier phrase "say __ again". The sound pressure level was targeted within a ±3 dB range. Intraoral air pressure (Po) was obtained using a buccal-sulcus approach. VOT, Po, maximum Po declination rate (MPDR), duration of the laryngeal devoicing gesture (LDG), occlusion duration, and the duration of the Po drop to baseline (atmosphere) to the onset of voicing (PDOV) were determined for each stop. Results: VOT was longer for the alveolar and velar stops compared to the bilabial stop. A constant LDG was observed for all stops regardless of place of articulation. Occlusion duration, however, was significantly shorter for the alveolar and velar stops compared to the bilabial stop. Aerodynamically, Po was greatest for the velar stop, intermediate for the alveolar stop, and smallest for the bilabial stop. MPDR index showed a slower rate of Po drop for the velar and alveolar stops compared with the bilabial stop. PDOV was found to be longer for /p/ than /t/ and /k/. Conclusion: Findings provide empirical evidence for the inter-related roles of Po, rate of Po change, and laryngeal factors in place-dependent variations of VOT. [ABSTRACT FROM AUTHOR]

Purpose: To determine if children with repaired cleft palate and normal velopharyngeal (VP) closure as determined by aerodynamic testing exhibit greater acoustic nasalance than control children without cleft palate. Method: Pressure-flow procedures were used to identify 2 groups of children based on VP closure during the production of /p/ in the word hamper: (a) children with repaired cleft palate and normal VP closure (n = 23) and (b) controls without cleft palate and with normal VP closure (n = 16). Acoustic nasalance scores were obtained for all children during the production of syllables with high-pressure consonants and sentences with low-pressure consonants (i.e., low-pressure sentences). Results: Nasalance scores were generally higher for children with repaired cleft palate and normal VP function as compared to controls; however, a significant difference occurred only for low-pressure sentences ( p = .005). Conclusion: Results partially support a pressure-sensitive theory of VP function in that some children with repaired cleft palate may achieve VP closure during the production of high-pressure consonants but fail to do so during the production of vowels and low-pressure consonants. Clinical implications are discussed. [ABSTRACT FROM AUTHOR]

Presents information on analyses to define some aerodynamic properties of one-way speaking valves designed for use with the tracheotomized patient. Methodology; Statistical analyses; Results; Discussion.