Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Health and Rehabilitation Sciences


Dr. Philip C. Doyle


The present work was comprised of a series of experiments that investigated the application of clear speech (CS) in a group of electrolaryngeal (EL) speakers. Three experiments were conducted to assess the impact of CS on three important aspects of EL speech. More specifically, Experiment 1 sought to identify the impact of CS on EL speakers’ word and consonant intelligibility; Experiment 2 examined the influence of CS on the acoustic characteristics of words and vowels in EL speech; and finally, Experiment 3 sought to identify the influence of CS produced by EL speakers on auditory-perceptual ratings by naïve listeners. Results revealed that overall word and consonant intelligibility were minimally different when EL speakers used CS compared to their everyday, ‘habitual’ speech (HS) (Experiment 1). Secondly, EL speakers’ use of CS significantly increased word durations, but did not have a substantial impact on fundamental and formant frequency characteristics of vowels (Experiment 2). Finally, due to the productive changes associated with CS involving a slower rate of speech, over-articulation, and increased mouth-opening, listeners judged EL speech to be significantly less acceptable to listen to when compared to HS. However, no significant effect of speaking condition was noted on listeners’ comfort levels (Experiment 3). Overall, findings suggest that the acoustic deficits in EL speech might be too complex to derive further benefit from CS in the areas of speech intelligibility, the acoustic structure of EL speech and/or auditory-perceptual ratings of EL speakers. Clinical implications and future directions for research are discussed.