Virtual characters and digital tutors are helping children and adults develop advanced social and language skills that can be tough to learn via conventional approaches. Children with autism can develop advanced social skills by interacting with a "virtual child" that they might not develop by hanging out with real children or teachers.
Cassell, J. (2008). Virtual Humans: A Tool for the Study and Teaching of Language and Social Interaction. Paper presented at the American Association for the Advancement of Science annual meeting, Boston.