Pictures or symbols may be used to represent a word, phrase, sentence or concept. These may be sequenced together, meaning two or more pictures are selected to create a phrase or sentence. Language is then spoken using either synthesized speech, digitized speech, or a combination. Synthesized speech uses a computer chip to generate spoken words from written text, based on phonetics. Digitized speech is an actual recording of an individual's voice, and requires more memory than synthesized speech.
Many devices allow language to be created on different levels.
The amount of language created utilizing different levels, in conjunction with sequencing, is limited only by the amount of memory in the device. Other systems have a single level or overlay, and allow generation of unique messages by combining or sequencing pictures in different ways. When traditional orthography is used messages can be spelled, or rate enhancement techniques such as abbreviation expansion or word prediction can be used . Selection Technique Selection techniques for accessing communication systems are varied and often unique. With an appropriate access evaluation, a selection technique can be identified for anyone.