RESUMO
Formant structure and vowel space are the most important acoustic characteristics of speech sounds. The purpose of this study was to determine formant frequency and vowel space in six Persian vowels. This cross-sectional descriptive-analytic study was performed on 60 Persian students of Tehran University of Medical Sciences [30 males, 30 females] with their age ranging from 18 to 24 years. The subject articulated six Persian vowels in isolation and data was recorded by real-analyzer software. Then, the first three formant frequency of each vowel was determined for each subject. Vowel formant frequency averages were measured separately for each vowel and each gender. Vowel space was plotted. The difference between F0 in two groups was compared by Leven and independent sample t tests. Maximum and minimum values of F0 in both group was related to // and /a/ [135 Hz in males and 239 Hz in females] and /i/ [146 Hz in males and 239 Hz in females]. Besides, F0 in females was significantly higher than males [p<0.001]. Maximum and minimum values of F1 were related to // and /i/. Furthermore, maximum and minimum values of F[2] were related to /i/ and /u/. Maximum and minimum values of F[3] were related to /i/ and /u/. The lowest vowels were // and /a/ and the highest was /i/. The frontest was /i/ and the backest was /u/. The spreadest vowel was /i/ and the roundest was /u/