Investigation and modeling of coarticulation during speech

Coarticulation is an important phenomenon of speech production, which involves in both the physical level concerned with articulators’ properties, and the planning stage for generating motor commands. The authors have proposed a model for coarticulation, named “carrier model”, to imitate the coarticulation mechanism. The carrier model is built on an assumption that articulation can be separated into a vocalic movement and a consonantal movement, and that coarticulation takes place within and between the movements as a modulation process. This study first verifies the assumption using a reconstructed text-independent articulatory movement based on observed articulatory data. The carrier model is elaborated based on those two movements and the look-ahead mechanism is employed to materialize the coarticulation. Coefficients of the carrier model were quantified via statistical analysis of articulatory data. A numerical experiment was conducted by implementing the carrier model in a physiological articulatory model (Dang and Honda, 2004). The results showed that the carrier model gave a good performance for simulating coarticulation.