• Speech Sound Disorders (SSD) put children at risk for literacy development, reduced peer acceptance, and limitations in vocational options. The high prevalence of SSD of unknown origin at 6 years of age (3.8%: Shriberg, Tomblin, & McSweeny, 1999), persisting to 8 years of age (3.6%: Wren et al., 2009), places idiopathic SSD among the most frequently occurring childhood disorders warranting public health resources for research in diagnostic assessment, treatment, and prevention.
  • Our research goals have been to understand the causal pathways that lead to each of three classes of SSD so that clinicians can select the appropriate intervention approach for each child, and researchers can conduct studies leading to the prevention of some subtypes of SSD.
  • Research goals have been pursued using a classification framework for SSD termed the Speech Disorders Classification System (SDCS). The finalized version of the SDCS has been used in genomic, neuroimaging, prevalence, normalization, and speech processing studies of children with idiopathic SSD and speakers with SSD in the context of complex neurodevelopmental disorders.


We are deeply grateful to the many Phonology Project alumni, research collaborators, and participants and their families for their significant contributions to the mission of this project over the past four decades. This research has been made possible with continuous support from the National Institute on Deafness and Other Communication Disorders (Grant DC000496) and a core grant to the Waisman Center from the National Institute of Child Health and Human Development (U54 HD090256).