Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 8-1982 Intelligibility of Speech Produced with an Artificial Larynx at Various Frequencies Sandra Arlene Merritt Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Communication Sciences and Disorders Commons Recommended Citation Merritt, Sandra Arlene, "Intelligibility of Speech Produced with an Artificial Larynx at Various Frequencies" (1982). Master's Theses. 1672. https://scholarworks.wmich.edu/masters_theses/1672 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. INTELLIGIBILITY OF SPEECH PRODUCED WITH AN ARTIFICIAL LARYNX AT VARIOUS FREQUENCIES by Sandra Arlene Merritt A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements for the Degree of Master of Arts Department of Speech Pathology and Audiology Western Michigan University Kalamazoo, Michigan August 1982 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. INTELLIGIBILITY OF SPEECH PRODUCED WITH AN ARTIFICIAL LARYNX AT VARIOUS FREQUENCIES Sandra Arlene Merritt, M.A. Western Michigan University, 1982 Word intelligibility scores of 21 listeners were used to test the hypothesis that speech intelligibility will vary systematically across speakers and fundamental frequency of electrolarynx vibration. Twenty-one listeners transcribed audio recorded lists of CVC utterances produced with an electrolarynx by 3 speakers at each of five fundamental frequencies. Comparative analysis of scores across frequencies and speakers were discussed in terms of: a) source transmission characteristics of "electrolaryngeal" speech, b) implications for diagnosis/therapeusis of alaryngeal speakers. Results indicated that intelligibility scores were significantly different between speakers and between frequencies within speakers. Maximum intelligibility scores were more highly correlated with certain frequencies for certain speakers. Results indicated that the relation of maximum intelligibility scores and fundamental frequency of vibration is speaker dependent. Additional post hoc information about phoneme error type substitutions, sex recognition, and quality judgments of acceptability of the speakers was related to intelligibility differences. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENT I would like to thank the three surviving members of my thesis committee: John Hanley, Robert Erickson, and Bill Dawson. A special thanks to my thesis advisor, John "Mick" Hanley, for his time, effort and unending patience. His instruction and guidance over the past year has made this learning experience a valuable one. Thanks to Robert Erickson for his generosity of clinical equipment and personal references. Thanks also to Bill Dawson for his technical assistance, continuous encouragement, and for demonstrating a genuine interest in this study. Appreciation is extended to the subjects who volunteered for the study, especially Carol Heermann-Jones, Carol French, and Gary Westra. Finally, a personal thanks to Craig Buffie, whose presence in my life has made many things possible - and doing them seem worthwhile. Sandra Arlene Merritt ii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 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University Microfilms International 300 N. Zeeb Road Ann Arbor, Ml 48106 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1319375 MERRITT, SANDRA ARLENE INTELLIGIBILITY OF SPEECH PRODUCED WITH AN ARTIFICIAL LARYNX AT VARIOUS FREQUENCIES WESTERN MICHIGAN UNIVERSITY M.A. 1982 University Microfilms International 300 N.Zeeb Road, Ann Arbor, MI 48106 Copyright ^ by MERRITT, SANDRA ARLENE All Rights Reserved Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ACKNOWLEDGMENTS............ ii LIST OF TABLES . .................. vi CHAPTER I. BACKGROUND AND PURPOSE . ..... i Introduction .................... i Statement of the Problem ............ 17 II. METHOD AND PROCEDURES. ...... ............. 19 Speakers .......... 19 Stimulus Materials ............... 20 Apparatus. ................... 20 Recording and Presentation of Stimulus Words . 22 III. RESULTS. ......... ............. 25 The Relationship Between Fundamental Frequencies (F0) of Electrolarynx Vibration and Speech Intelligibility Scores for Speakers. .......... 28 Analysis of Phoneme Error by Frequency ..... 37 Summary. , ......... 44 IV. DISCUSSION ............. 46 The Relationship Between Fundamental Frequency (F0) of Electrolarynx Vibration and Speech Intelligibility Scores for Speakers. 47 Analysis of Phoneme Errors by Frequency. .... 54 V. SUMMARY AND CONCLUSIONS. ........... 67 P u r p o s e . ................ • • • . 67 Experimental Design. .... ... 67 Findings and Conclusions........ .. 69 iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS — CONTINUED APPENDICES. ................. ........... 72 A. PB-50 Word Lists Selected From the USA Monosyllabic Intelligibility Test Word Lists. 73 B. Schematic of Adjusted Electrolarynx Modified Switch Circuitry............. 76 C . Sound Pressure Levels for Unloaded and Loaded Systems at Five Test Frequencies. .......... 77 D. Recording Order for Word Lists (1,2,3,4,5) and Frequencies 94 Ilz. (A), 120 Hz, (B), 160 Hz., (C), 212 Hz. (D), 245 Hz. (E) for Speaker 1, Speaker 2, and Speaker 3 . , . 7 8 E . Rank Order of Intelligibility Scores and Acceptability Ratings (Low to High) and Order of Frequency Presentation for Each Group and Speaker. Frequency A - 94Hz., Frequency B= 120 Hz., Frequency C= 160 Hz., Frequency D = 212Hz., and Frequency E=245Hz......... 79 G . Sound Spectra of the Vowel Sound "a" (as in "father") Produced With the Electrolarynx Set at the Five Test Frequencies ........ 81 F. Sound Spectra of the Vowel "ee" (as in "bean") Produced With the Electrolarynx Set at the Five Test Frequencies........ .. 80 H . Sound Spectra of the Electrolarynx Set at the Five Test Frequencies, 94Hz., 120Hz., 160Hz., 212Hz., 245Hz. 82 I . Rank Order of Mean Intelligibility Scores (Parenthesis) From Low to High and Their Corresponding Frequencies For Each Speaker Across Groups Frequency A=94Hz., B=120Hz., C=160Hz., D=212Hz., and E=245Hz. ............. 83 J. Instructions For Speakers and Listeners. .... 84 iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS — CONTINUED APPENDICES K. Informed Consent Release Form. 8 6 L. Listeners Response Sheet ............ ... .... 87 M. Matrix of Percentage of Total Phoneme Error Substitutions by Speaker. Percentages of Frequencies A(94Hz.) , B(I20Hz.) , C(160Hz.),'; ; D(212Hz.), E(245Hz.) are Listed Sequentially . 88 BIBLIOGRAPHY . • • . • . • . • . • • .. 91 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF TABLES 1. Intelligibility Scores (Percentages) for Each