Production of Vowels by Electrolaryngeal Speakers Using Clear Speech.

BACKGROUND/AIMS: This study examined the effect of clear speech on vowel productions by electrolaryngeal speakers. METHOD: Ten electrolaryngeal speakers produced eighteen words containing /i/, /ɪ/, /ɛ/, /æ/, /eɪ/, and /oʊ/ using habitual speech and clear speech. Twelve listeners transcribed 360 words, and a total of 4,320 vowel stimuli across speaking conditions, speakers, and listeners were analyzed. Analyses included listeners' identifications of vowels, vowel duration, and vowel formant relationships. RESULTS: No significant effect of speaking condition was found on vowel identification. Specifically, 85.4% of the vowels were identified in habitual speech, and 82.7% of the vowels were identified in clear speech. However, clear speech was found to have a significant effect on vowel durations. The mean vowel duration in the 17 consonant-vowel-consonant words was 333 ms in habitual speech and 354 ms in clear speech. The mean vowel duration in the single consonant-vowel words was 551 ms in habitual speech and 629 ms in clear speech. CONCLUSION: Finding suggests that, although clear speech facilitates longer vowel durations, electrolaryngeal speakers may not gain a clear speech benefit relative to listeners' vowel identifications.

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.

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.

Variable perception of white noise in ambiguous phonetic contexts: the case of /p/ and /f/.

The roles of spectro-temporal coherence, lexical status, and word position in the perception of speech in acoustic signals containing a mixture of speech and nonspeech sounds were investigated. Stimuli consisted of nine (non)words in which either white noise was inserted only into the silent interval preceding and/or following the onset of vocalic transitions ambiguous between /p/ and /f/, or in which white noise overlaid the entire utterance. Ten listeners perceived 85% /f/s when noise was inserted only into the silent interval signaling a stop closure, 47% /f/s when noise overlaid the entire (non)words, and 1% in the control condition that contained no noise. Effects of spectro-temporal coherence seemed to have dominated perceptual outcomes, although the lexical status and position of the critical phoneme also appeared to affect responses. The results are explained more adequately by the theory of Auditory Scene Analysis than by the Motor Theory of Speech Perception.