Medical Center, for his assistance and counsel concerning the statistical analysis of the data. Thanks are due to Sister Lourdes Leal for her assistance in the collection of the data and to the subjects and judges who unselfishly participated in this study.The writer also wishes to express his gratitude to his wife Patricia for her continued encouragement and understanding during this period of graduate study. Ill

This study was designed to investigate the formant frequencies of phonated and whispered productions of five test vowels (/i/,/u/, /æ/, /Δ/, and //). Each test vowel was sustained twice in isolation—once phonated, once whispered—by 20 adult female subjects. The phoneme represented by each recorded production was identified independently by 11 listeners. Only those samples identified by 6 or more of the listeners as the vowel intended were retained for a further (acoustic) analysis. An acoustic spectrum of each retained sample was obtained to permit formant measurements. To provide the clearest formant delineation possible in our lab, the phonated samples were analyzed by broadband spectrography and the whispered samples by very narrowband spectrography. This report presents the formant frequencies (F I -F 3 ) of the test productions as measured from the acoustic vowel spectra and the formant-freqneney differences between the pbonated and whispered productions. In general, the results showed a trend for whispered vowel formants to be higher in frequency than phonated vowel formants, but that trend was only strongly evident for F 1 .

Acoustic wave-period variation (jitter) and acoustic wave-amplitude variation (shimmer) associated with vowel pronations representing a range of vocal roughness were investigated. Twenty normal-speaking adult males phonated each of the vowels /u/, /i/, /Λ/, /a/, and /æ/, first normally and then with simulated abnormal vocal roughness. Twenty hoarse adult males, each presenting a medically diagnosed laryngeal pathology, also produced each of the five test vowels. To provide a measurable presentation of the frequency and amplitude variations of interest, each recorded vowel was band-pass filtered to isolate the fundamental frequency component. Relations of the jitter and shimmer indices (obtained from the filtered vowel waves) to acoustic spectral noise levels and to roughness ratings for the vowel phonations were studied. The findings supported the hypothesis that increases in vowel acoustic wave variability (estimated by period or amplitude variation or both) are associated with increases in vowel spectral noise levels and perceived vowel roughness. The findings also suggested, for most of the vowels studied, that cyclic peak amplitude variation may provide a better index of perceived roughness than cyclic period variation. Vowel spectral noise levels, however, may provide a more clinically useful indicant of vowel roughness than the waveform variability indices derived from the filtering procedure employed in this study.

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Twenty normal-speaking adult females sustained seven-second productions of the vowels /u/, /i/, /Λ/, /a/, and /æ/ first normally and then with simulated vocal roughness at one intensity. Recordings of the vowels were rated for roughness on a five-point equal-appearing intervals scale by 11 trained judges. Each production was also analyzed to produce a 3-Hz bandwidth frequency-by-amplitude acoustic spectrum in which the level of inharmonic, i.e., noise, components was measured in dB SPL. Noise levels, averaged over selected frequency ranges from 100 to 8000 Hz, for each vowel production correlated highly with the median roughness ratings for the productions. High (≥0.97) and significant multiple correlation coefficients were obtained between each vowel’s 100-Hz section noise levels from 100 to 2600 Hz and its median roughness rating.