Modeling coarticulation in continuous speech

Modeling coarticulation in speech has been largely limited to short sequences and/or limited phonetic context. We introduce a methodology for modeling both formant frequency and bandwidth in continuous speech, allowing examination of sentencelevel coarticulation. The model represents continuous trajectories as a combination of overlapping local trajectories, which are represented by a weighted-addition of acoustic event targets by sigmoidal coarticulation functions characterized by slope and position. Estimation is achieved using a combination of hill-climbing and grid-search, with global target, joint slope for identical contexts, and local position parameters. We evaluate model performance for two speakers using an intelligibility test that compares vocoded model output to a purely vocoded and a natural condition.