Processor

Rate Enhancement
Rate enhancement is the process of reducing the amount of selections needed to be made to generate a certain number of characters. As a result of decreasing the number of necessary selections, the rate of the selection system is increased. Rate enhancement is typically divided into two groups: encoding techniques and prediction techniques.
	Encoding Techniques
	There are various types of encoding techniques used in augmentative communication systems to speed up the rate of communication. The most common are numeric codes, abbreviation expansion, and semantic encoding. The following paragraphs give a brief description of each technique.
	Numeric Codes
	Numeric codes may be used to stand for a word, a phrase, or a complete sentence. The individual using the system simply enters one or two numbers that represent the desired item, and the communication system outputs the stored word, phrase, or sentence.
	Abbreviation Expansion
	In abbreviation expansion techniques, a shortened version of a word or phrase (abbreviation) is input to the device and the abbreviation is automatically expanded into the desired word or phrase. Click Here to Link to Abbreviation Expansion Software
	Semantic Encoding
	Semantic encoding, or Minspeak, uses icons (pictoral representations) to represent words, phrases, or sentences. The icons can have more than one meaning and may be combined with other icons to form different meanings. For example, an icon with a picture of an apple might stand for "food". An apple combined with an icon for "go" might stand for "Let's go out to eat." Click Here to Link to Manufacturer
	Prediction Techniques
	Prediction techniques may also be used to speed up the rate of communication by automatically altering the order of letters or icons presented based on the previously entered selections. The following paragraphs summarize two types of predition techniques - icon prediction and word prediction/completion.
	Icon Prediction
	Icon prediction is a feature incorporated in some minspeak devices to permit easier recall for the user when large numbers of sentences, words, and phrases are stored. Icon prediction has an LED associated with each symbol. Therefore, only certain symbols are lit up at the beginning, middle, and end of an icon sequence based on the context in which it is used.
	Word Prediction and Word Completion
	Word completion software incorporates a window on the computer screen in which a list of the most likely words appear based on the previously entered letters. Word prediction, however, provides a list of the most likely words based on the previously entered words, not letters. For both packages, as soon as the desired word is displayed in the menu, the user may select the word by selecting the number listed beside it. Click Here to Link to Word Prediction Software
Vocabulary Expansion
Due to the fact that it is difficult to display all of the vocabulary on a display at one time, vocabulary expansion is used to increase the available vocabulary through the use of levels. One method of vocabulary expansion is the use of dynamic displays. Dynamic displays change the selection set displayed on the screen every time a new level is selected.
Vocabulary Storage
A very important aspect to augmentative communication systems is the ability to store vocabulary. Most AC devices are delivered with a basic vocabulary system (i.e. alphabet) and allow users to increase the items stored in his or her vocabulary with use. However, there are some systems that have built-in vocabularies that do not allow expansion.
Text Editing
Text editing techniques allow the user of the communication device to make changes to a word that was not pronounced correctly by a speech synthesizer. By using a text editor, the user can simply go back to the word that needs corrected without having to retype the entire sentence.

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Page last updated by Jill Serafin, 27 May, 1999