Observation and Modeling of Lingual Coarticulation in the Planning Stage

This study investigates and models anticipatory coarticulation taking place in different portions of tongue during speech production. Based on articulatory observations, we reconstructed generalized articulatory movement from articulatory data. It is found that the movements of the tongue dorsum and tongue tip can be treated as a carrier wave and a modulation in the articulation. Accordingly, a “carrier model” is proposed to describe this mechanism of anticipatory coarticulation at the planning stage. A model based learning process was used to refine the parameters of the carrier model. The simulations using the optimized coarticulation model and the learned typical phonetic targets were consistent with the observations within an average error of 0.18 cm in the articulatory space. The listening test showed that the synthesized sounds were improved by implementing the carrier model.