'Compensatory articulation' refers to the fact that normal speakers immediately compensate for the displacement of an articulator during vowel production. This form of motor equivalence is an important feature of the human speech production system. By examining how normal and brain-damaged subjects speak while holding a small 'bite block' between the teeth, it is possible to learn more about the neurological and functional organization of speech motor control.

We are developing a new method for treating speech and nonspeech oral motor control difficulties caused by stroke. Specifically, we are examining the efficacy of visual biofeedback provided by Electromagnetic Midsagittal Articulography (EMA) in treating speech and nonspeech oral errors produced by talkers with focal damage to the left hemisphere speech zone. This research also allows us to test prevailing theories concerning the functional and neural bases of adult communication disorders, including oral apraxia and apraxia of speech.

Children's speech clearly sounds quite different than speech produced by adults. Nevertheless, children are understandable most of the time. This research focuses on how children's vowels differ from those produced by adults, and what effect these acoustic features have on perception. We are particularly interested in vowel-inherent spectral change and how such patterns change during development.

Are there age-dependent differences in the amount of gestural overlap used to produce speech sounds? We are exploring this issue with (1) direct kinematic recording of lips, tongue, and jaw; (2) spectral and durational analyses of talkers' productions; (3) perceptual tests which examine the extent to which coarticulatory information can be perceived by normal adult listeners.