Acoustic and perceptual characteristics of the Spanish fricatives

This study deals with the relation between the spectral representation and the perceptual identification of the Spanish fricatives and affricates. Several spectral representations have been analyzed: FFT-derived linear cepstrum, mel cepstrum coefficients, LPC cepstral coefficients and the first four statistical moments. Quadratic discriminant analysis including the leaveone-out method have been carried out on a large database. For this particular classification procedure, both the order of every spectral parametrization and the order of the temporal trajectory of those parameters have been optimized. The results indicate that a low order representation performs satisfactorily and that a three order temporal trajectory is adequate to encode the dynamics of the fricatives. The best classification rates were obtained by the cepstral (79.5%) and linear cepstrum coefficients (75.2%). They attained a correlation coefficient with respect to the perceptual identification of 0.78 and 0.75, respectively.