Sudden speechlessness (SS) is commonly experienced by patients admitted to critical care units. Although literature findings document challenges associated with periods of SS, the prevalence is unknown. The purpose of this study is to determine the prevalence and characteristics of adult SS patients in four critical care units at a university-affiliated tertiary care hospital. Data are collected on 9 randomly selected days over a 4-month period. The daily prevalence of SS ranges from 16% to 24% in each unit. Characteristic data collected includes patient age, gender, medical diagnosis related to SS episode, type of speechlessness, days since SS began, and communication strategies in use. Respiratory intubation related to various clinical diagnoses is the main cause for SS. Use of multiple specific strategies to convey needs during SS periods are identified. Follow-up studies to further define the prevalence of SS in settings beyond the critical care environment are recommended.