The purpose of this study is to teach children with autism who do not produce sounds or words to vocalize sounds or words by using the stimulus-stimulus pairing (SSP) procedure. The investigators will use SSP, an intervention based in behavior analysis, to try to help the child vocalize sounds. A vocal recorder will also be sent home so that the caregiver can record the child's vocalization at home. The caregiver will then be asked to return this so that the investigators can listen to it. By doing this, the investigators hope to learn if the treatment helps increase the child's vocalizations at home. Some children in the study will receive treatment immediately. Some children may enroll in the study now but not receive intervention until a later date. All children in the study will receive treatment within one year of enrolling in the study.