Identifying vowels in CVC syllables: Effects of inserting silence and noise

Abstract

Listeners were asked to identify natural vowels in /d_d/ context under various deletion conditions. Deletion intervals ranged from 60% to 90% of the syllable duration (measured from initial burst to final closure onset) and were centered about the midpoint. The deleted syllable portions were replaced with either silence or broadband noise. In one experiment, the three syllable types used were /did/, /ded/, and /dud/; in the other experiment, the three syllable types were /dΙd/, /dεd/, and /dΛd/. To ensure that identification performance was based solely on spectral information, tokens were selected such that, within an experiment, average syllable duration was approximately equal across types. Identification performance in the 60% and 70% deletion conditions was not substantially worse than for full syllables [cf., W. Strange, J. J. Jenkins, and T. R. Edman, J. Acoust. Soc. Am. Suppl. 1 61, S39 (1977)]. Even the 90% deletion conditions yielded performance well above chance, indicating that significant vowel information is contained in the first and last 10 or 15 ms of the syllable. Results will be discussed in terms of residual acoustic cues.