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

Abstract

Listeners were asked to identify natural vowels in Id_d/ context under various deletion conditions. Deletion intervals, which were centered about the syllable midpoint, ranged from 60% to 90% of the syllable duration and contained either silence or broadband noise. In one condition, the three syllable types were Idid/, Ided/, and Idud/; in the other condition, the three syllable types were /dld/, /ded/, and/dxd/, Identification performance in the 60% and 70% deletion conditions was not substantially worse than for full syllables. Even the 90% deletion conditions yielded performance well above chance, indicating that significant coarticulatory information for vowels is contained in the first and last 10 or 15 msec of the syllable. For the short-vowel stimuli (fdId/, /ded/, and IdAd/) in the 90% deletion condition, a series of discriminant analyses were performed to assess the relative contribution of several acoustic variables to the statistical separation of the vowel categories. Several different combinations of acoustic variables (including formant frequencies at particular temporal locations and formant frequency differences over time) were sufficient to yield significant separation of the three vowel categories. However, in general, the performance ofthe discriminant classification program correlated only weakly with the identification performance of the listeners.

The relative roles of vowels and consonants in discriminating talker identity versus word meaning

“…Consistent with the general perspective that speech evolved through imposing articulatory gestures on a vowel-based carrier signal ͑Dudley, 1939;Traunmüller, 1994, a variety of data from linguistic processing point to the critical role of the dynamic properties of speech. One kind of evidence comes from "silent-center" vowel experiments, in which listeners have been found to be surprisingly accurate in correctly identifying vowels embedded in a CVC context even when the center portion of the vowel segment is set to silence ͑e.g., Parker and Diehl, 1984;Strange, 1989aStrange, , 1989bJenkins et al, 1994͒. In fact, vowel perception under these conditions is more accurate than when vowel-centers are presented in isolation ͑Strange, et al, 1976;Verbrugge and Rakerd, 1986͒. Hillenbrand and Nearey ͑1999͒ have further shown that whereas synthetic vowels generated with steady-state formants are correctly identified about 75% of the time, stimuli that track naturally occurring formants produce approximately 90% correct identification. According to these studies, it is the dynamic, time-varying onsets and offsets of vowels that are critical to correct phonetic identification.…”

Asymmetries in English Vowel Perception Mirror Compression Effects

“…The vowel pairs tested are /e/-/o/, /ɑ/-/u/, and /i/-/e/. The idea is to examine a small number of vowel contrasts that are representative of the types examined in prior studies: a pair differing along the backness/rounding dimension, which is generally found to be the most discriminable type of contrast; a pair differing in more than one step along the height dimension (high vs. low) as well as rounding, which should be roughly comparable to the backness/rounding contrast; and a pair differing in only one step (high vs. mid) on the height dimension, which is generally found to be the least discriminable type of contrast [Whalen, 1983;Parker and Diehl, 1984;Repp and Lin, 1989].…”

Perception of silent-center syllables by native and non-native English speakers

“…Flege, 1995;Imai et al, 2005;and Flege and MacKay, 2004͒. To investigate the hypothesis that even proficient non-natives may be less able to identify speech sounds based on partial acoustic information, the present study used a silent-center syllable perception task ͑Strange et Parker and Diehl, 1985͒ to compare the ability of native and non-native listeners to identify consonantvowel-consonant ͑CVC͒ syllables from which varying degrees of the vowel center had been removed.…”