Estimation of the movement trajectories of non-crucial articulators based on the detection of crucial moments and physiological constraints

This study develops a mathematical model that estimates the movements of (linguistically) non-crucial articulators in speech production, which provides a systematic way to study the relationship between the behaviors of crucial and non-crucial articulators; crucial articulators are those essential for realizing a speech task. The underlying assumption of our model is that non-crucial articulatory movements are governed by the physiological constraints in relation to the corresponding crucial articulators as well as by the contextual constraint from the nearest crucial time of the non-crucial articulator. These constraints have been generally assumed in the speech production literature, but they have not been incorporated directly into articulatory models. The crucial articulatory moments in an utterance are automatically determined by a novel forced-alignment algorithm for articulatory trajectories, which uses the inherent physical properties of crucial articulatory movements. Experimental results suggest that the proposed algorithm is capable of estimating non-crucial articulatory positions well in both neutral and emotional speech, significantly better than the simple interpolation of crucial points. Index Terms: non-crucial articulators, articulatory modeling, emotional speech