David J Zajac, MA, PhD


Adjunct Associate Professor, Speech and Hearing Sciences, School of Medicine

Faculty Fellow, Frank Porter Graham Child Development Institute

  • PhD, Communication Disorders, University of Pittsburgh
  • MA, Speech Pathology and Audiology, University of Pittsburgh
  • BS, Psychology, University of Pittsburgh
  • CCC-SLP and Fellow, American Speech Language Hearing Association

He is director of speech-language pathology and the pressure-flow laboratory in the Adams School of Dentistry Craniofacial Center. Zajac specializes in the assessment and treatment of children and adults with craniofacial anomalies. He has over 25 years experience with this population. He has written many book chapters and/or research articles on normal and disordered speech production. He is an ASHA Fellow and past associate editor for the Journal of Speech Language and Hearing Research.

Zajac is currently the principal investigator of two NIH research grants. “Speech of Young Males with Fragile X Syndrome” is funded by the National Institute of Child Health and Human Development through June 2014. “Development of Stop Consonants in Children with Repaired Cleft Palate” is funded by the National Institute of Dental and Craniofacial Research through March 2018.

Research Interests

Cleft lip-palate, speech production, speech aerodynamics, speech acoustics, velopharyngeal function

Research Summary

As a clinical speech-language pathologist and speech scientist, Zajac’s research focuses on speech production in general and speech associated with craniofacial anomalies in particular. He is currently conducting an NIDCR-sponsored project investigating the emergence of stop consonants and vocabulary words in young children with repaired cleft palate, children with otitis media, and typically-developing children. He and his team are also investigating the effects of dental and occlusal anomalies on speech production.

Availability to Mentor

Undergraduate/college student, graduate student, undergraduate DDS or DH student, and junior faculty member