Augmentative and alternative communication (AAC) is the use of symbols, aids, strategies, and techniques to enhance the communication process. This includes sign language, various communication boards, and both manual and electronic devices help those who have trouble with communication.

Some examples of AAC include: 

1. Unaided communication systems – Rely on the user's body to convey messages. Examples include gestures, body language, and/or sign language. One advantage of unaided communication communication systems is that it does not require any technology beyond the person's body.

2. Low-tech AAC - Any type of aid that does not require batteries or electricity. This includes things like a simple pen and paper to write messages on, as well as pictures boards, that can be carried to aid communication. On picture boards, users can point to images, words, pictures, drawings, or letters in order to communicate their message. The pointing might be done with the user's hands, other body parts, eye gaze, or a pointer held in the hands or mouth. 

3. High-tech AAC - Any aid that requires electricity or batters. This includes specialized devices, software, smartphone applications, electronic communication boards, and keyboards. Many high-tech AAC devices are Speech Generating Devices, which means they can produce digitized speech when the user either types a message or presses on images, words, or letters.

Below are just some examples of what AACs can look like

Left to Right: Images 1, 2, 3, 5, 6 © User:Poule / Wikimedia Commons / CC-BY-SA-3.0. Image 7 © User Joxerrazabala / Wikimedia Commons / CC-BY-SA-3.0.  Image 4 in public domain.

Electronic Fluency Devices are devices intended to help improve the fluency of people with stutters. They do this by playing the sound of the user's own voice back into their ear, slightly altered. 

There are two main types of Electronic Fluency Devices :

Delayed Auditory Feedback (DAF)- Delayed Auditory Feedback devices play the user's voice back delayed by a fraction of a second. DAF devices may resemble hearing aids or headphones with a microphone. There are also apps that can use DAF on phone calls.

Frequency Altered Feedback (FAF)- Frequency Altered Feedback devices are similar to DAF but rather than delaying the user hearing their own voice, they change the pitch at which the user hears their own voice.