Clinician, research assistant Institute for Childhood Aphasia, Palo Alto, California, 1966-1970. Program specialist for communication disorders Los Angeles County Superintendent of Schools Office, 1970-1980. Associate professor communication disorders California State University, Los Angeles, 1981-1984, professor communication disorders, 1984-1992.
Research professor education and human development Vanderbilt University, Nashville, 1992-1997. Research professor department hearing and speech science Vanderbilt University Medical School, since 1993, research professor special education, since 1997. Consultant in field, since 1970.
Fellow American Speech-Language-Hearing Association (vice president clinical affairs 1988-1991). Member California Speech-Language-Hearing Association (certified), Tennessee Association Audiologists and Speech-Language Pathologists, Council for Exceptional Children, Society Research in Child Development, American Educational Research Association, Phi Beta Kappa, Phi Kappa Phi.