Lately I have helped quite a few families with purchasing different types of assistive technology (AT) devices. AT is technology that aids people with disabilities in performing functional activities that are difficult or impossible unless adapted. This might include adapted eating supplies, special computer keyboards, adapted toys, or equipment for blind or deaf persons. The following link discusses augementative communication (AAC) devices, which is a computerized output system that helps the person talk. I have seen children as young as 2 years old use an AAC device. Depending upon the child's level of cognition and motion in hands, the pre-AAC devices (e.g. Big Mac or Jelly Bean switch) that control battery-operated toys can be used beginning at around 12-18 months of age.
Assistive Technology for Children Who Have Cerebral Palsy: Augmentation Communication Devices