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Speech errors, or "slips of the tongue", have been studied in attempts to understand the speech production process, to investigate phonological units and rules, and to provide insights into historical linguistic change. The present study examines speech errors and their relation to segment durations in word-initial /sp, st, sk/-clusters produced under rapid repetition conditions by six adult native speakers of English. Fifty percent of the errors produced could be classified as repetition errors; these were examined for duration in the initial clusters, both error and corrected productions. General results following from analysis of the data were: (1) Error clusters and their component segments were consistently longer in duration than their subsequent and immediate corrections. (2) The clusters /sp/ and /sk/ are longer than /st/, which may be attributable to the faster moving, more highly innervated tongue tip musculature involved in the production of Is/ and It/, compared with the heterorganic clusters. (3) The stop consonant in a given cluster appears to determine the overall cluster duration, since the duration of /s/ remains fairly constant irrespective of context. In light of the results, it was speculated that the excessive duration of the cluster (or of its component parts) violated a timing constraint on the production of an utterance, necessitating recalibration and correction of the error. It was further inferred that feedback must be present in order for the system to recognize the duration error, to compare it with planned output, and finally to execute a correction. Two types of feedback were considered necessary for the adequate functioning of a speech production model, which would also allow for speech perception: (a) continuous auditory feedback, which is supplemented by (b) intermittent proprioceptive feedback, both of which are used in perceiving input ,:and manipulating output. Such a system provides a plausible account of speech error production as described in this study. The hypothesized variable servomonitor system advocated here (and in other studies) in general provides an efficient means for producing, monitoring and correcting speech production. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate

Previous studies have shown that analogy instruction can be applied effectively in science education and motor skill acquisition; however, little is known about the application of analogy in speech motor performance. In four experiments, analogy instructions were tested in the speech domain. The first experiment (Chapter 2) used focus group methodology to establish a set of analogies that related pitch variation during speech production to a ‘waves at sea’ metaphor. The analogies were then used to elicit speech with different pitch variations. Analogy instructions were more effective than explicit instructions for eliciting speech with minimum pitch variation (i.e., monotonous speech). In the second experiment (Chapter 3), the influence of both analogy and explicit instructions on the perception of speech parameters invoked by maximum pitch variation was examined. Pitch variation in analogy instructed speech was perceived to be greater and more natural than when explicit instructions were provided. In the third experiment (Chapter 4), stress resistance in analogy instructed speech performance was evaluated. Analogy instructed speech performance was demonstrated to be significantly more stable under a psychologically stressful condition than explicitly instructed speech. The last experiment (Chapter 5), investigated the cognitive load of analogy on different components of the working memory system during speech performance. It was found that analogy instructions tended to place more cognitive load on the visual component of working memory than explicit instructions. The findings of the four experiments inform the application of analogy in speech motor skill performance in general, and contribute to understanding the mechanisms that underpin analogy within a working memory framework. The work also has significant potential for application in speech-language pathology treatment. / published_or_final_version / Human Performance / Doctoral / Doctor of Philosophy

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The rhythmic organization of speech into regular intervals (i.e. isochrony), is a strong perceptual phenomenon. However, Investigators have been unable to demonstrate the existence of isochrony in production data. It is hypothesized in this study that the intended rhythm of a speaker is in fact isochronous, but that this is obscured by several distorting influences which introduce durational irregularity at the syllable level, e.g. intrinsic duration, stress, position of the syllable in a phrase and number of syllables in a phrase. It is proposed that removing the predictable durational irregularities will yield a more regular signal, reflecting the (hypothesized) Intended Isochronous rhythm of the speaker. The latter two sources of distortion introduce progressive durational irregularity or "warping" which can be readily incorporated into an automated "dewarplng" procedure. A computer program was devised to compensate, at the syllable level for these two sources of distortion. The former two sources are not amenable to such an automated procedure, and were therefore not included. The "dewarping" program was run on the speech amplitude envelopes of two speakers, one French and one English. The results indicate that, for the French speaker, dewarping does remove some of the durational Irregularity, yielding a more regular amplitude envelope. For the English speaker, no such Improvement in regularity is obtained. This indicates that the dewarping used, which presumes the syllable as "unit" of dewarping, is appropriate for syllable-timed languages such as French, but inappropriate for stress-timed languages such as English. It therefore provides some support for isochrony in French at the syllable level. Finally, the results also give support to the hypothesis that the degree of warping perceived as regular in speech perception studies corresponds to the degree of dewarping which, conversely, yields the most regular speech amplitude envelope; however, further experimentation is necessary to determine the optimum values of the parameters of the dewarping function. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate

published_or_final_version / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Education / Master / Master of Philosophy

No description available.