RecruitingBehavioural interventionTrial of Center-Based vs. In-Home Pivotal Response Treatment (PRT) in AutismThe aim of this clinical trial is to compare the efficacy of a 16-week center-based Pivotal Response Treatment (PRT-C) versus home-based Pivotal Response Treatment (PRT-H) in targeting social communication deficits in young children with autism spectrum disorder (ASD) with significant language delay. The two groups will also be compared to a control group that consists of children who are receiving treatment as usual (TAU).