Different sign languages have developed in different countries. Each word is then spelled out. Fingerspelling often is used with sign language for spelling of proper names, technical terms, and the like. Thousands of pictures are needed for a modest vocabulary size. Meanings must be taught since most words are not naturally represented by pictures.
Literacy is required.
The small number of words that are used for the majority of communication. The information is then analyzed to produce a report of various quantitative summary measures of communication performance. There are a variety of different ways to send messages. With good motor control, an individual can produce communication symbols by using speech, gestures, sign language, fingerspelling, writing, head shaking, eye blinks, and other facial and body movements. When an electronic AAC device is used, the device transmits the communication in response to input from the user.