First Advisor

Robert C. Marshall

Term of Graduation

Spring 1973

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Speech: Speech and Hearing Sciences






Speech perception -- Sex differences, Voice, Vowels



Physical Description

1 online resource (3, vi, 50 pages)


The purpose of this study was to investigate the effects of speaker-sex-difference on listeners' perception of vocal roughness in the vowel [ӕ] produced by normal male and female speakers. In a previous investigation by Wendahl (1963) it was found that when listening to two synthesized vowels, of equal aperiodicity, judges tended to rate the lower pitched vowel as being more vocally rough. If this is true for listeners' perception of human vowel productions as well then it might be advantageous for voice clinicians, when making vocal roughness assessments, to regard male and female speakers as two separate populations in view of the inherent pitch differences between the sexes.

In this current investigation, pairs of vowels produced by normal adult male and female speakers were presented to 10 speech pathologists (5 males and 5 females). Each vowel pair contained one male and one female production of the vowel [ӕ] which had been assigned equal roughness ratings in a previous judging task. The 50 vowel pairs contained 10 pairs of vowels at each of five roughness rating levels. The 10 judges were required to listen to each of the 50 pairs and to make a forced choice selection of the most vocally rough production within each pair.

The findings in this study revealed that for the 50 vowel pairs the judges selected the vowels produced by males as being more vocally rough a significantly greater proportion of the time. With respect to the five roughness rating levels, judges chose the male produced vowels as being rougher a significantly greater proportion of the time at rating levels one, three and five but illustrated no significant preference between the sexes at rating levels two and four. Further analysis revealed that the five male judges selected the vowels produced by males as being the rougher a significantly greater proportion of the time for all 50 pairs at each of the five roughness rating levels. The five female judges, on the other hand, illustrated no significant preferences between the sexes for the 50 vowel pairs. They did show a significant preference for the males at rating level one, a significant preference for the females at rating level two but no significant at rating levels three, four and five. In addition, male judges illustrated substantially greater inter-judge agreement and intra-judge reliability for this judging task than did the female judges.


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A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Speech: Emphasis Speech Pathology and Audiology.

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