Project Summary Approximately 50% of children with cerebral palsy (CP) have the speech disorder dysarthria. Dysarthria is difficult to identify in young children because its characteristics (speech subsystem features) overlap with features of early typical development. Quantitative standards for differentiating typical from atypical speech subsystem development in children do not currently exist. This research seeks to improve early identification and treatment of dysarthria in children with CP by creating clinically accessible, data-based developmental standards that allow us to differentiate between typical and atypical auditory-perceptual speech subsystem features in children. To do this, we will validate an English adaptation of the pediatric version of the well- established Bogenhausen Dysarthria Scales (BoDyS-Kid), including 31 subsystem-based perceptual speech features and 10 domains. The research will capitalize on speech samples from 573 typically developing (TD) children, collected in the first funding cycle; and 74 children with cerebral palsy (699 longitudinal speech samples). We will collect new data from 1300 speech language pathologists (SLPs) who will make auditory- perceptual ratings of children’s speech using the BoDyS-Kid, comprising the first ever large-scale comprehensive study of the development of speech subsystem based auditory-perceptual features in English- speaking children. Specific aims are: 1.) To quantify the maturation of auditory-perceptual speech subsystem features and domains in typically developing children. 2.) To quantify the maturation of auditory-perceptual speech subsystem features and domains in children with cerebral palsy. 3.) To identify and quantify auditory- perceptual speech subsystem features and domains that discriminate among clinical groups and are associated with speech intelligibility for children with CP and TD. Products of this research will be a.) a theoretically grounded and validated clinical tool for auditory-perceptual assessment of speech subsystem features/domains in English speaking children for use by practicing clinical SLPs to support differential diagnosis of speech disorders; b.) a set of normative standards that quantify the course of acquisition and define an expected range of variability by age for auditory-perceptual speech subsystem features/domains; c.) quantitative characterization of longitudinal patterns of subsystem feature/domain acquisition in children with CP (with and without dysarthria), and d.) foundational knowledge of specific features/domains that best differentiate between typical and dysarthric speech development, and a quantitative understanding of the relative contributions of subsystem features/domains and clusters thereof to children’s speech intelligibility. Results will advance the development and validation of evidence-based clinical speech assessment methods for pediatric dysarthria that will provide a clinically accessible explanatory basis for inte...