ABSTRACT
100 persons were included in this study, 50 of each sex. These were divided into 3 age groups; children, adults and elderly. All the included persons were nonsmokers, nonhabitual or professional voice users and free from any general medical or local laryngeal disease. Acoustic analysis of their voices was carried out, by the CSL [Computerized Speech Lap], using sustained phonation of three vowels, /a/, /i/, /u/ at comfortable and habitual pitch of the examined speakers. As regards the fundamental frequency, it was concluded that the female-to-male ratio, was as much as 1.5 in adults and elderly persons. The highest mean fundamental frequency was reported in children, then declined to reach its adult value, followed by slight increase to reach its elderly value. As regards the mean relative jitter, the male values were proved to be higher than the female values, especially in adults, with only little differences in children. It was also proved that the jitter values tended to decrease with increasing the fundamental frequency. The highest shimmer values were obtained in adults especially adult males. The harmonic-to-noise ratio, was found to be affected by the variations of the ages and sexes, a condition which could be explained by the changes of the fundamental frequency