Lawrence J. Raphael

Preceding vowel duration as a cue to the perception of the voicing characteristic of word-final consonants in American English.

A number of studies in the literature have stated that the duration of a vowel is a significant cue to the voicing characteristic of the consonant that follows it. The present study investigated the effect of varying preceding vowel duration upon the perception of word‐final stops, fricatives, and clusters in synthetic speech. A variety of minimal CVC (C) pairs was synthesized and the vowel of each was varied over a range of values derived from durations found in real‐speech samples. It was found that, regardless of the cues for voicing or voicelessness used in the synthesis of the final consonant or cluster, listeners perceived the final segments as voiceless when they were preceded by vowels of short duration and as voiced when they were preceded by vowels of long duration. Discrimination tests revealed that when the voicing characteristic is cued by vowel duration, perception is continuous rather than categorical.

Stop-consonant recognition: Release bursts and formant transitions as functionally equivalent, context-dependent cues

Three experiments assessed the roles of release bursts and formant transitions as acoustic cues to place of articulation in syllable-initial voiced stop consonants by systematically removing them from American English /b,d,g/, spoken before nine different vowels by two speakers, and by transposing the bursts across all vowels for each class of stop consonant. The results showed that bursts were largely invariant in their effect, but carried significant perceptual weight in only one syllable out of 27 for Speaker 1, in only 13 syllables out of 27 for Speaker 2. Furthermore, bursts and transitions tended to be reciprocally related: Where the perceptual weight of one increased, the weight of the other declined. They were thus shown to be functionally equivalent, context-dependent cues, each contributing to the rapid spectral changes that follow consonantal release. The results are interpreted as pointing to the possible role of the front-cavity resonance in signaling place of articulation.

Some experiments on the sound of silence in phonetic perception

The results of several experiments demonstrate that silence is an important cue for the perception of stop-consonant and affricate manner. In some circumstances, silence is necessary; in others, it is sufficient. But silence is not the only cue to these manners. There are other cues that are more or less equivalent in their perceptual effects, though they are quite different acoustically. Finally, silence is effective as a cue when it separates utterances produced by male and female speakers. These findings are taken to imply that, in these instances, perception is constrained as if by some abstract conception of what vocal tracts do when they make linguistically significant gestures.

Durations and Contexts as Cues to Word-Final Cognate Opposition in English

Many perceptual and acoustic studies of word-final cognate opposition have relied mainly on isolated synthetic utterances and have usually concluded that one or another of the potential cues is primar

Disfluencies in cluttered speech

UNLABELLED The purpose of this study was to examine the nature and frequency of occurrence of disfluencies, as they occur in singletons and in clusters, in the conversational speech of individuals who clutter compared to typical speakers. Except for two disfluency types (revisions in clusters, and word repetitions in clusters) nearly all disfluency types were virtually indistinguishable in frequency of occurrence between the two groups. These findings shed light on cluttering in several respects, foremost of which is that it provides documentation on the nature of disfluencies in cluttering. Findings also have implications for our understanding of the relationship between cluttering and typical speech, cluttering and stuttering, the Cluttering Spectrum Hypothesis, as well as the Lowest Common Denominator definition of cluttering. EDUCATIONAL OBJECTIVES At the end of this activity the reader will be able to: (a) identify types of disfluency associated with cluttered speech; (b) contrast disfluencies in cluttered speech with those associated with stuttering; (c) compare the disfluencies of typical speakers with those of cluttering; (d) explain the perceptual nature of cluttering.

Tongue musculature and the feature of tension in English vowels.

Electromyographic techniques were employed to discover which, if any, intrinsic and extrinsic tongue muscles displayed a difference in overall amount of activity corresponding to the traditional tense-lax distinction between members of the English vowel pairs /i-I/, /e-epsilon/, and /u-u/. Although some muscles revealed a consistent difference, most did not. Even for those muscles where a tense-lax difference was found, the data do not support the notion that tension was a necessary of sufficient differentia of production.

Tongue Position in Rounded and Unrounded Front Vowel Pairs

Traditional articulatory descriptions of front rounded and unrounded vowel pairs have assumed that tongue height is the same for the members of the pairs /i-y/, /e-ø/, and /ε-œ/. The electromyographic, articulatory synthetic, and acoustic investigations carried out in this study indicate that, in Dutch, the rounded member of the pairs /i-y/ and /e-ø/ was centralized. In the /ε-œ/ pair, however, the rounded vowel bears a different relationship to its unrounded counterpart.

Vowel normalization: the role of fundamental frequency and upper formants

Abstract Some vowel normalization schemes assume the perceptual exploitation of f0 and F3 information. These schemes implicitly predict that access to such information should improve listeners’ classification of vowels in a mixed-speaker condition relative to their classification in a blocked-speaker condition. In this study listeners classified naturally produced phonated and whispered (no f0 information) vowels in which formants above F2 were either present or filtered out. Results provided some support for the use of f0 in vowel normalization; results for F3 were inconclusive. An unexpected finding was that upper formants were more important for whispered vowel classification than for phonated vowel classification.

Speech prosody in cerebellar ataxia.

Persons with cerebellar ataxia exhibit changes in physical coordination and speech and voice production. Previously, these alterations of speech and voice production were described primarily via perceptual coordinates. In this study, the spatial-temporal properties of syllable production were examined in 12 speakers, six of whom were healthy speakers and six with ataxia. The speaking task was designed to elicit six different prosodic conditions and four contrastive prosodic events. Distinct prosodic patterns were elicited by the examiner for cerebellar patients and healthy speakers. These utterances were digitally recorded and analysed acoustically and statistically. The healthy speakers showed statistically significant differences among all four prosodic contrasts. The normal model described by the prosodic contrasts provided a sensitive index of cerebellar pathology with quantitative acoustic analyses. A significant interaction between subject groups and prosodic conditions revealed a compromised prosody in cerebellar patients. Significant differences were found for durational parameters, F0 and formant frequencies. The cerebellar speakers demonstrated different patterns of syllable lengthening and syllable reduction from that of the healthy speakers.

Relationship of recorded EMG signals to within‐ and cross‐utterance acoustic variation

Analysis of simultaneous acoustic and EMG recordings of one speaker of New York English producing /əpVp/ utterances under several conditions shows differences between inter‐ and intrautterance interactions. For three anterior genioglossus insertions (♯1–♯3) and one posterior insertion (♯4), the peak activation amplitude relevant to articulation of the vowel was measured. Amplitude differences reliably differentiated target vowels. For vowel/muscle pairs with significant amplitudes, activity duration and phasing of the peak within the activity were also measured. Despite strong correlations among the peak amplitudes for the anterior insertions, these measures differed in their correlations with measures of F0, F1, and F2, both within and across utterances. Overall, F2 correlated best with ♯1/duration, F1 with ♯2/amplitude, and F0 with ♯2/amplitude. For /ɪ/, intertoken F2 variation correlated best with ♯3/phasing, F1 with ♯2/amplitude, and F0 with ♯3/phasing. The posterior ♯4/duration correlated best with /...