A fundamental question is: What are the basic building blocks of speech? To answer this question, I am working in a number of areas.
In speech recognition, I am looking at new acoustic models, such as Linear Dynamical Models, factorial-HMMs and other graphical models that can represent speech not as 'beads on a string' but as streams of interacting factors. I've investigated ways to automatically find an inventory of suitable units to model, as well as working on other alterntives to phonetic units, such as graphemes. One long-standing interest is the use of phonological/acoustic/articulatory features and articulatory measurement data as a tool to develop models of speech.