E.+Encoding

In AAC devices, vocabulary is represented with letters, words or picture symbols. No symbol system is better than another though some may be more useful to the communicator than others. For example, someone with a visual impairment may be able to perceive black line drawings better than detailed photographs.
 * Symbolic Representation and Encoding**


 * Critical Assumptions:**
 * 1) Symbols must be encoded to represent language
 * 2) The ability to encode is a developmental skill that begins to emerge in infancy and develops throughout childhood and into adulthood
 * 3) Symbolic meaning is arbitrary though salient features in the picture can convey "hints"
 * 4) The arbitrary metaphoric and linguistic associations of symbols must be overtly taught for the communicator to understand them
 * 5) Access to the alphanumeric system is crucial to support literacy and mathematics acquisition
 * 6) Encoding core vocabulary words with pictures is difficult because core words do not lend themselves to symbolic representation


 * Symbol Features to Consider:**
 * Foreground color
 * Background color
 * Color or black and white
 * Drawing or photograph
 * Detailed or simple
 * Ratio of complexity in foreground:background
 * Flat or glossy
 * Smooth or with tactile embellishment
 * Pair the written word with the symbol or not


 * Types of symbols:**
 * Letters and words
 * Line drawings- black and white or color
 * Photographs
 * Tactile symbols- an object or part of an object represents a concept (a piece of chain might represent the idea of swinging)


 * Systems for Encoding Symbols:**

Sequencing multi-meaning symbols or Minspeak/Semantic Compaction
 * [apple] + verb = eat
 *  [apple] + noun = food
 *  [rainbow] + apple = red
 * Advantage- a smaller symbol set yields a larger amount of vocabulary choices
 * Disadvantage- concepts may not be immediately clear to communicator

Single Meaning Pictures Spelling and word prediction [graphic of word prediction]
 * Single or multiple pages (tangible and dynamic) with single meaning symbols for each vocabulary target
 * Each picture has one meaning/concept and often has the written word included (this only benefits literate communicators and communication partners)
 * Advantage- communicator is required to grasp only one concept per picture
 * Disadvantage- a much larger symbol set is required necessitating increased navigation or decreased choices
 * Any array of letters/numbers can be created with low or high-tech systems
 * In high-tech systems, word prediction provides a list of possible word based on initial letter selection (when spelling “this”, after the ‘t’ is selected the words “this, the, that, those, to” [most common ‘t’ words] appear on a list from which the AAC user can choose)
 * Word prediction decreases the number of required actuations required and my provide cognitive supports for poor spellers (common among AAC communicators)
 * Advantage- any utterance can be created
 * Disadvantage- Literacy skills required; may be slower than picture communication