A probabilistic model of integration of acoustic cues in FV syllables

The interaction of consonantal and vocalic segments in FV syllables regarding identification of place of articulation of fricatives has been studied. A probabilistic model for integration of acoustic information in both segments is proposed. The model weights each segment’s contribution and integrates them in order to resemble listeners’ perception. First, the perceptual validity of the model has been assessed. Overall correlations of the probabilistic model with listeners’ responses to a set of natural and conflicting-cue (place of articulation) FV syllables were 0.88 and 0.74, respectively. The results showed that in order to increase correlations, the model should weight F and V segments differently for each fricative, and even for each vocalic context, since listeners gave more or less importance to the vocalic transition depending on the particular fricative and vocalic context. Acoustic analysis was also carried out computing the probabilistic model with a posteriori probabilities for F and V segments obtained with quadratic discriminant analysis. The results were disappointing, indicating that usual statistical methods fail to extract coarticulatory information. This prevents ASR systems from taking advantage of the enhancement of the characteristics of the consonant in the FV condition with respect to the F condition.