Abstract:
Speakers with velopharyngeal incompetence,produce hypernasal speech across voiced
elements.During the production of vowels,due to the defective velopharyngeal mechanism,oral
cavity gets coupled with the nasal cavity.This coupling may introduce resonances of nasal cavity
in the resulting vowel sound.Speech signal of eight cleft palate children with various VP opening
have been studied. By considering normal and nasal vowel formants of normal speakers as
reference, we have observed that variation in the spectrum of their speech occurs due to various
types of VP opening due to abnormal coupling of oral and nasal cavity. In case of large VP
opening an extra peak or nasal resonance is seen to appear around 600Hz and for small VP
opening around 950 Hz. As the VP opening or cut of the cleft palate increases, the first formant
reduces and lowers the extra formant.
