GAL and Dravet syndrome: Figures 1b, 2a, and 2b, respectively, include SDCSS prevalence findings for participants with DS, FXS, and GAL. Figure 3 includes both descriptive statistical findings for the prevalence percentages in Figures 1 and 2 and the inferential statistical findings comparing 22q speech and motor speech prevalence findings with findings for each of the three other comparison groups.