The purpose of this study was to assess the perceptual role of brief synthetic consonant-vowel syllables as cues for vowel perception in children and adults. Nine types of consonant-vowel syllables comprised of the stops [b d g] followed by the vowels [i a u] were synthesized. Stimuli were generated with durations of 10, 30, or 46 ms, and with or without formant transition motion. Eight children at each of five age levels (5, 6, 7, 9, and 11 years) and a control group of eight adults were trained to identify each vowel in a three-alternative forced-choice (3AFC) paradigm. The results showed that children and adults extracted vowel information at a generally high level from stimuli as brief as 10 ms. For many stimuli, there was little or no difference between the performance of children and adults. However, developmental effects were observed. First, the accuracy of vowel perception was more influenced by the consonant context for children than for adults. Whereas perception was similar across age levels for stimuli in the alveolar context, the youngest children perceived vowels in the labial and velar contexts at significantly lower levels than adults. Second, children were more affected by variations in stimulus duration than were adults. This finding was particularly prominent for the syllable [ga], where the dependency on duration decreased with age in a nearly linear fashion. These findings are discussed in relation to current hypotheses of vowel perception in adults, and hypotheses of speech perception development.

The importance of different acoustic properties for the perception of place of articulation in prevocalic stop consonants was investigated from a developmental perspective. Eight adults and eight children in each of the age groups, 5, 6, 7, 9, and 11 years, listened to synthesized syllables comprised of all combinations of [b d g] and [i a]. The synthesis parameters were adapted from Blumstein and Stevens [J. Acoust. Soc. Am. 67, 648-662 (1980)], and included manipulations of the following stimulus variables: formant transitions (moving or straight), noise burst (present or absent), and voicing duration (10 or 46 ms). Identification performance was high for all age groups across most stimulus types. Formant transition motion generally was not necessary for accurate identification, and there was no difference between age groups in terms of the perceptual weight placed on this cue. Furthermore, the results did not support the salience of duration as a developmental cue to place of articulation. The presence of a burst improved identification for the velar and alveolar places of articulation for all age groups, but was particularly important for the 11-year-olds and adults. These findings indicate that children, by age 5, do not rely on dynamic formant motion any more than adults do, and that the ability to integrate acoustic cues across regions of spectral change shows developmental patterns.

The purpose of this study was to assess the perceptual role of brief synthetic consonant–vowel syllables as cues for vowels in children and adults. Stop–consonant syllables were synthesized in the context of three vowels, [i, u open aye], with durations of 10, 30, or 46 ms. These syllables were produced with bursts, and contained formant motions and/or formant onset frequencies appropriate for each stop–consonant place of articulation. Eight children at each of five age levels, 5, 6, 7, 9, and 11, and a control group of eight adults were trained to identify the vowel as either /i/, /u/, or /open aye/. The findings showed that children and adults extracted vowel information at a generally high level from stimuli as brief as one glottal pulse (together with initial burst). However, significant effects were found for age, vowel, duration, and transition type. The age effects manifested that even quantal vowels were not identified in an adult-like manner by young children. The duration and transition-type effects revealed that vowel perception was sometimes better for longer syllables with moving formant transitions. Overall, these perceptual findings indicate that syllable identification is more salient in adults than children. [Work supported by NIH, DC00464.]

This research extends previous developmental studies on the perception of the [m]–[n] distinction in CV syllables [R. N. Ohde and K. Haley, J. Acoust. Soc. Am. 92, 2463(A) (1992)]. With only one exception, three talkers for each age level of 3, 5, 7, adult female, and adult male produced VC syllables consisting of either /m/ or /n/ in the context of four vowels /iæuopen aye/. Two productions of each syllable were modified using waveform editing techniques so that the distribution of place of articulation cues for consonant perception could be determined. Ten adults identified the place of articulation of the nasal from several murmur and vowel transition segments. Preliminary findings indicate that the salience of the place of articulation feature from spectral discontinuity cues is substantially weaker in VC syllables than CV syllables, particulary in children’s productions. The findings for the perception of speech segments will be discussed relative to (1) The independence of formant transitions in the vowel and the murmur spectrum as cues to place of articulation in VC syllables, and (2) the developmental role of spectral change between the vowel and the murmur in syllable acquisition. [Work supported by NIH, DC00464.]

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