Persian vowel formants an investigation and comparison between Persian children 7-9 years old and persian adult 18-22 years old

Introduction: Formant structure is one of the most important acoustical characteristics of sound. the relationship between first three formants is the main component of perceptual categorization by the listener. The quality and the kind of one vowel is related to its formant. Material and methods: The goal of this descriptive-analytical study was to assign and compare formant structure of Persian vowels between 50 Persian children 7-9 years old from two separate schools in Tehran (25 boys and 25 girls) and 50 adults aged between 18 and 22 from persian students and employees at the rehabilitation sciences faculty of Iran (25 men and 25 women). Six persian vowels (/i/,/e/,/æ/,/a/,/o/,/u/) were produced using simple sample. The first three formant of persian language vowels were obtained and compared between two groups of male adults and school boys and also female adults and school girls. Results: Fundamental frequency, first three formants of each vowel (F1, F2, F3), band frequency of each formant, and the intensity of each formant in each vowel were obtained and recorded by speech studio software and laryngograph device Conclusion: In all groups, /æ /vowel was the lowest height vowel and /i/ vowel is the highest high one. In addition, /i/ vowel was the high front vowel and /u/ vowel was the high back vowel one in all groups. The results of comparison of formant structure of Persian language vowels in two groups of male adults and school boys, and female adults and school girls suggested that all quantities of formant frequency of the Persian vowels in adults is lower than children, by what it says that male and female adults had lower formant frequencies in compare with boys and girls. These findings were similar to pervious same studies. The differences observed between children and adults are due to different vocal tract length and different size of resonator cavities.