Velar Stop Consonants Research Articles

Central and monaural factors in the summation of F2 and F3 transition onsets

Previous research has indicated that F2 and F3 transition onsets of velar consonants may summate to simulate a “burst‐like” feature. This F2‐F3 summation may explain why subjects make more stop responses to a velar stop‐semivowel series than to a bilabial series. When the onset amplitude of F2 and F3 is reduced for these stimuli, there is no significant difference in the number of stop responses made to the velar and bilabial consonants. Similarly, when the third formant is eliminated entirely, the number of velar stop responses is reduced. Thus, there is evidence for the perceptual integration of velar F2 and F3 transition onsets. The current research was designed to determine whether the locus of perceptual summation is central (binaural) or monaural. Subjects identified dichotically presented bilabial and velar stop consonants and semivowels. An isolated formant was presented to one ear and the remaining two formants were simultaneously presented to the other ear. Monaural perceptual integration predicts that there should be no difference in the stop‐semivowel boundary location for velars and bilabials when F2 and F3 are presented to different ears. [Work supported by NSF and NIMH.]

Speech perception by rhesus monkeys: The voicing distinction in synthesized labial and velar stop consonants

Monkeys were presented with synthetic speech stimuli in a shock-avoidance situation. On the basis of their behavior, perceptual boundaries were determined along the physical continua between /ba/ and /pa/, and /ga/ and /ka/, that were close to the human boundaries between voiced and voiceless consonants. As is the case with humans, discrimination across a boundary was better than discrimination between stimuli that were both on one side of the boundary, and there was generalization of the voiced-voiceless distinction from labial to velar syllables. Unlike humans, the monkeys showed large shifts in boundary when the range of stimuli was varied.

Effects of vocalic context, place of articulation, and speaker's sex on “voiced” stop consonant production

A study was made of voice-onset time in initial “voiced” (prevoiced and short lag) labial, dental and velar stop consonants. Ten male and ten female English-speaking subjects produced isolated CVC syllables. Prevoicing occurred more frequently and was greater in duration before high vowels than before low vowels. Prevoicing also occurred more frequently and was of greater duration for labial and dental stops than for velar stops. Short-lag duration was greater preceding high vowels than preceding low vowels, but short-lag stops occurred more frequently in the context of low vowels than in the context of high vowels. Short-lag productions were of greater duration and occurred more frequently in the case of velar stops than in the case of dental and labial productions. Male subjects exhibited both more frequent occurrence of voicing lead and greater prevoicing duration than females. Although females employed the short-lag mode more frequently than males did, female speakers were found to produce shorter voicing lags than males.

Voicing contrast: perceptual and productive voice onset time characteristics of adults.

This study was designed to examine the status of voice onset time (VOT) in identification and production of word-initial voiced and voiceless labial, apical, and velar stop consonants for 20 English-speaking adults. Synthetic speech stimuli were constructed for four continua including BEES/PEAS, BEAR/PEAR, DIME/TIME, and GOAT/COAT. VOT values for 30 productions of the same words examined in the identification task were determined from spectrographic measurements. Analyses of the perceptual data revealed significant differences among labial, apical, and velar stops for the VOT 50% crossover and lower and upper limits of the phoneme boundary, but not for boundary width. In production of voiced and voiceless stops, reliable differences for mean VOT were shown between all cognates and among places of articulatory constriction within voicing category. The latter finding was primarily related to the labial/velar comparisons. Variability among individual speakers was demonstrated in the percentage of voiced stops associated with VOT values in the lead portion of the continuum, whereas all subjects evidenced productions in the short lag range. Comparisons between identification and production demonstrated high consistency for VOT characteristics in that few productions coincided with the perceptual phoneme boundary or contrasting voicing category.