UNLABELLED:This paper aims to provide a better understanding of the nature of functional communication activities so that assessment and treatment efforts are based on a theoretical framework and empirical data. Three sources of information are discussed. The first is the Activity/Participation dimensions of the World Health Organization's International Classification of Functioning, Disability, and Health. The second source is existing assessments of functional communication. The final source is data obtained from observational studies conducted in our research unit. The studies have observed the everyday communication of people with aphasia, people with Traumatic Brain Injury (TBI), and patients in hospital. The simplification of real-life communication in the WHO classification scheme, the variability of item sampling in existing assessments, and the complexity of communication observed in real-life settings has led to the conclusion that there are three levels of functional communication assessment: generic, population-specific, and individualized. Clinicians may choose which level suits their purpose. When clinicians routinely choose from a range of sophisticated functional assessments to inform their therapy, the seed that Martha Taylor Sarno planted and nourished for the past 30 years or more will truly flourish throughout the world of speech-language pathology. LEARNING OUTCOMES:As a result of this activity, participants will (1) understand the theoretical framework and data base that motivates assessment and treatment of functional communication activities, (2) be able to discuss the World Health Organization's Classification of Functioning, Disability and Health and (3) gain information about functional assessment and observational sampling of real world communication activities across three levels.