Augmentative and alternative communication (AAC) is the general term used to refer to systems of communication that assist people with different degrees of speech impairment or communication limitations. It assists people with autism, traumatic brain injury, ALS, cerebral palsy, and more. AAC tools allow people to express their thoughts, ideas, and emotions more effectively while also easing communication difficulties. There is a wide range of AAC tools, from no/low tech to high tech tools, and it ultimately depends on the capability of the user; some users may require the use of a combination of different tools. AAC communication systems can be aided or unaided. Aided communication requires external equipment in addition to the body while unaided communication relies on the user's body to convey messages (gestures, facial expressions, sign languages). Aided communication tools can range from something as basic as a pencil to a high tech device that reproduces speech.
Non-technical or low-technical tools are systems of communication that either do not require external power or require external power but they are easy to program. Non-tech/ low tech tools are the foundation for the later use of high-tech devices. Common non-technical communication tools are choice boards and communication boards which assist users to convey messages by pointing (physically or with eye-gaze direction) at objects, symbols, pictures or a combination. In the classroom,

Accessibility
Definition of input device for students with special needs:

mobility or severely disabled.
An example of hardware input device is the Intellikeys keyboard. It has a large surface area which is designed for students who have motor control difficulties. It plugs to any Mac or computer with a USB port and it comes with six standard overlays to meet the needs of a wide variety of users.
Wordprediction programs are software input devices that assists individuals who have difficulties with typing their thoughts and ideas, either because of motor difficulties or because the user struggles with the writing process. The software "predicts" the user's intent word based on the person's syntax and spelling. A specific wordprediction software isWordQ+SpeakQ, which integrates three features: word prediction, text to voice and voice recognition. This software is ideal for students who physically or mentally struggle with typing/writing.