AUTOMATIC CLASSIFICATION OF THE SPANISH FRICATIVES [THETA] AND [S]

A simple threshold-based method is described which permits automatic d istinction between the Spanish fricatives [theta] and [s] in the initi al position by means of a measurement of energy and a rough determinat ion of the spectral composition as the zero-crossing rate. All signal analysis (including word endpoint and fricative detection) is carried out automatically. The system was tested using a series of words conta ining all the [theta, s]-vowel combinations possible in normal Spanish , thus allowing for possible effects of fricative-vowel coarticulation . To study sex-related differences, 10 men and 10 women were used as s peakers. Both sex and fricative-vowel coarticulation affected correct classification rate. The overall correct classification rate was 93.5% (94% for men and 92% for women). A classification procedure using a d iscriminant function obtained assuming Gaussian statistics achieved al most identical results.