There are some individuals with autism who acquire little to no functional speech. In this case, it is often recommended to implement an Alternative and Augmentative Communication (AAC) system such as Picture Exchange Communication System (PECS) or a Voice-Output Communication Aide (VOCA; aka Speech Generating Device, SGD). Technology has come so far in recent years that hand-held devices such as the Dynavox Tango and the Maestro are widely available making allowing individuals with autism to have communication devices that meet their diverse needs.
It is important that individuals with autism are taught to use a functional form of communication and that is best accomplished in the natural environment. A study done in 1998 (see link at the end of this post) by Maureen Schepis and her colleagues showed that students could be taught to use VOCAs utilizing naturalistic teaching techniques. It has been shown in multiple studies that teaching functional communication skills, whether verbal or AAC, is most effective when done in the natural environment using naturally reinforcing items and activities.
In general, when doing something preferred the student is more likely to be motivated to request, respond and comment. Parents, teachers and peers can set up opportunities for communication and encourage spontaneous communication. When functional communication is addressed in this way communication is likely to improve faster, be maintained over time and generalize to other settings, materials and communication partners. For more information on how to implement AAC in the classroom, check out the implementation toolkit published by Dynavox.