Speech-training systems providing visual feedback of vocal tract shape are found to be useful for improving vowel articulation. Estimation of vocal tract shape, based on LPC and other analysis techniques, generally fails during stop closures, due to very low signal energy and unavailability of spectral information. Based on estimated area values and line spectrum pair (LSP) coefficients before and after stop closure in vowel-consonant-vowel (VCV) syllables, least-squares bivariate conic and cubic polynomial surfaces were generated and used for shape estimation during stop closure by performing 2D interpolation. Implementation of the technique with automated processing of /aCa/ syllables successfully estimated the place of articulation during closure segments of velar, alveolar, and bilabial stops. The technique can be used to provide visual feedback to improve production of stop consonants.
Bibliographic reference. Shah, Milind S. / Pandey, Prem C. (2007): "Estimation of place of articulation in stop consonants for visual feedback", In INTERSPEECH-2007, 2477-2480.