They are used by, e.g., movie theaters to list the current roster of films, churches to display the titles of sermons, and other buildings, people, and institutions whose signs are required to change on a regular basis.
[1] Communication boards can be as basic as letters of the alphabet or contain extensive options of words, phrases, pictures, and symbols of common items or actions.
AAC and SGD software allow different forms of synthesized and digitized speech to be used through voice or message banking.
[3] Other high-tech AAC works as a grid of buttons that can be utilized by gazing or controlled by a mouse that has pre-recorded messages installed to supplement spoken word.
[4] Analog or low-tech communication devices are common among children with autism spectrum disorder who are non-verbal.