Acoustic Analysis of Glottal Stop Occurrence before Initial Vowels in Persian Words

The present study, in the context of computational linguistics and acoustic phonetics, attempted to determine the acoustic features of glottal stop before the word initial vowels in the Persian language and to answer the question whether this sound is a consonant or is the characteristic of the initial vowel in the Persian. The research test groups consisted of three groups: (a) nonword group in which the vowel is located after a consonant except glottal stop, (b) nonword group in which the presence of glottal stop is clear before the vowel, and (c) the group containing 30 words of Farsi language which begin with vowels. The three groups were read and recorded by 16 sample members at the studio. Then, they were subjected to acoustic measures, duration, first formant, intensity and spectral tilt of vowels evaluation using The Praat software. The numerical values obtained were analyzed based on mean indices, variance and Scheffe test. It was found that the criteria for the existence of the glottal stop consonant in the word group were not verified; as a result, the complete stop that has the acoustic characteristics of a consonant does not exist before the word initial vowels in the Persian language. Therefore, the incomplete obstruction can be taken as the phonetic process that is added at the beginning of the initial vowel production, and it makes that vowel glottalized.