This workshop will provide information on the current definition of Apraxia of Speech and its clinical perceptual features. The information will cover (1) speech features that are used to differentially diagnose AOS, (2) speech features that frequently occur in adults with AOS but that are not differential, and (3) speech features that are used to rule out the presence of AOS. Data on the prevalence of the disorder will be provided. An overview of the types of assessments used and the need for the development of standardized tests of AOS will also be covered. Some information on acoustic measures associated with AOS will be provided. Finally, samples of speech of clients with AOS will be presented and diagnostic criteria identified as part of break-out group participation.