Consonant/vowel ratio as a cue for voicing in English

Abstract

Several experiments investigate voicing judgments in minimal pairs like rabid-rapid when the duration of the first vowel and the medial stop are varied factorially and other cues for voicing remain ambiguous. In Experiments 1 and 2, in which synthetic labial and velar-stop voicing pairs are investigated, the perceptual boundary along a continuum of silent consonant durations varies in constant proportion to increases in the duration of the preceding vocalic interval.In Experiment 3, it is shown that speaking tempo external to the test word has far smaller effects on a closure duration boundary for voicing than does the tempo within the test word. Experiment 4 shows that, even within the word, it is primarily the preceding vowel that accounts for changes in the consonant duration effects. Furthermore, in Experiments 3 and 4, the effects of timing outside the vowel-consonant interval are independent of the duration of that interval itself. These findings suggest that consonant/vowel ratio serves as a primary acoustic cue for English voicing in syllable-final position and imply that this ratio possibly is directly extracted from the speech signal.Twenty-five years ago, Denes (1955) reported an interesting phenomenon regarding the perception of phonological voicing by English listeners. He found that a voiceless final fricative in a synthetically constructed monosyllable could be heard as having either the plus or minus value of the English voicing feature, depending on the relative duration of the vowel and final fricative itself for words like his and hiss.

Timing relations in speech and the identification of voice-onset times: A stable perceptual boundary for voicing categories across speaking rates

“…The author did not report on whether or not the stimuli contained durational ratios similar to those of voiced stops in natural speech, and the use of stimuli with voiceless VOTs throughout may well have created large ratios that precluded the identification of voiced consonants. Utman's results also contrast with numerous studies showing that vowel length in synthesized and natural speech syllables influences listeners' classification of the voicing category of syllable-initialstops (e.g., Green et al, 1994;Port & Dalby, 1982;Sawusch & Newman, 2000). However, none of these studies addressed the issue of whether or not a criterion ratio estimated from speech production data serves to predict listeners' identifications of voicing categories.…”

On the nature of rate-dependent processing during phonetic perception

“…Up to this point, we have limited our consideration to individual syllables. But there are numerous demonstrations that the effective rate information influencing phonetic identification is not confined to the syllable itself, although, interestingly, the rate of the target syllabledoes appear to have the greatest influence (e.g., Port & Dalby, 1982;Summerfield, 1981). For example, changing the rate of a precursor sentencecan influence the identification of a subsequent syllable (e.g., Port & Dalby, 1982;Summerfield, 1981).…”

“…But there are numerous demonstrations that the effective rate information influencing phonetic identification is not confined to the syllable itself, although, interestingly, the rate of the target syllabledoes appear to have the greatest influence (e.g., Port & Dalby, 1982;Summerfield, 1981). For example, changing the rate of a precursor sentencecan influence the identification of a subsequent syllable (e.g., Port & Dalby, 1982;Summerfield, 1981). And although this type of effect is often quite small, it is robust, even when the changes in rate are confined to syllables that are at least one syllable removed from the target item (Miller, Green, & Schermer, 1982).…”

On the internal perceptual structure of distinctive features: The [voice] contrast

“…The likelihood that a listener will identify a postvocalic stop as [+voice] is known to be affected by the preceding vowel's duration (Denes, 1955;Raphael, 1972), the stop's own closure duration (Lisker, 1957), and by the ratio of these two durations to one another (Kohler, 1979;Port & Dalby, 1982), with the consonant: vowel (C:V) duration ratio being small for [+voice] stops and large for [−voice] ones. Two acoustic properties that contribute to the percept of the low frequency property, F 1 at vowel edge and closure voicing, not only interact perceptually with this ratio, but do so in a way that depends on their own integration.…”