Visualization research has paid little attention to individuals with intellectual developmental disabilities (IDDs). This lack of attention is problematic due to the fact that the consumption of visualization relies on a significant number of cognitive processes, including the ability to read and process language and retain information, and these processes often operate differently for IDD individuals. We argue that visualization should be used to communicate with and by IDD populations, who are currently unsupported. We identify three elements of visualization design that may improve how people with IDDs communicate with data based on prior efforts and empirical findings to examine the influences of chart types, data continuity, and chart embellishments on this communication. In doing so, we hope to bridge the gap between IDD individuals and data in support of their self-advocacy and self-determination, and thus recognizing this underserved group in the conversational visualization design space.