A considerable number of studies have demonstrated that augmentative and alternative communication (AAC) is effective in increasing speech production in some children with autism spectrum disorder (ASD). Thus, this study aimed to (a) investigate the effects of a Picture Exchange Communication System (PECS) Phase IV protocol on the acquisition of spontaneous augmented requests, (b) evaluate the impact of progressive time delay and synthetic speech output on the development of vocal requests, and (c) determine the participants' preferences for each modality after reaching mastery. A multiple-baseline design across four children with ASD was used to measure the acquisition of augmented and vocal requests during the transition from low-tech to high-tech AAC systems. During a natural condition (i.e., playtime), a modified PECS Phase IV protocol was applied to teach the participants to request by producing multisymbol messages (e.g., I WANT + names of a preferred item) using an iPad as well as vocalizations. After mastery, the participants' preference for using the modified PECS Phase IV app or the communication book was assessed by comparing the response allocations. The preliminary results suggest that the modified PECS protocol can be used to transition from a low- to high-tech communication modality.
Keywords: Augmentative and alternative communication (AAC); Picture Exchange Communication System (PECS); Speech production; Speech-generating devices (SGD).