Baseline PhaseDuring baseline, the researcher provided the children with time to communicate, used expectant delay (i.e., paused and looked expectantly at the child), and ensured access to the aided AAC system. After the child took a communicative turn and/or completed an action during play (e.g., pointing to the girl and then the bus), the instructor waited a minimum of 1 s to ensure the child’s turn was complete and then provided a spoken model (e.g., The girl’s gonna hit the bus!). The spoken models reflected the child’s communicative behaviors, including what the child looked at, pointed to, played with, and/or said (Siegel & Cress, 2002). If a participant said or did nothing following the researcher’s presentation of a spoken model, the instructor provided an expectant delay (i.e., paused for the child’s typical turn transfer timet5 s and looked expectantly at the child) before providing another spoken model. Each spoken model consisted of a brief utterance that contained at least two of the vocabulary words included on the AAC system for that particular play scenario. The instructor provided a minimum of 30 spoken models within each session