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Home > AAC Features > Selection Set

Selection Set Features

The selection set [G] is all the items that can be used to compose a message for communication. Some devices or techniques involve a very simple selection set; others have a large and complex set, but each technique or device is characterized by a number of separate selection set features.

Before we get to the selection set features, however, I want to remind you to think about the "selection set" of able-bodied people, the vocabulary that speakers have available at all times. Consider these facts:

  1. Speakers generally have a huge vocabulary to choose from: Did you know that the standard desktop dictionary has 150,000 words in it? And in English, the common "everyday vocabulary" includes approximately 20,000 words?
  2. A speaking vocabulary is available immediately whereas AAC vocabulary has to be located and then retrieved for production. That slows down communication considerably.
  3. Speakers do not have to be able to recognize symbols that represent the words they want. Toddlers have a very large vocabulary well before they can recognize all the pictures or words for these concepts. AAC users have to be able to recognize either a visual or an auditory symbol in their selection set to make a choice.

Keep these things in mind as you look at the following features:

1. Vocabulary Size

Vendors often brag about the vocabulary capacity or the size of the symbol set available in their device. However, this is not the same as the size of the vocabulary available to the user. They may be talking about the dictionary that can be used for programming. We need to focus attention on how much vocabulary the USER will have available for communication, what I call the "functional" vocabulary.

2. Symbol Types

The symbols are the way an item in the selection set is represented for the AAC user. Although we tend to focus on visual symbols, AAC symbols can also be auditory or tactile.

3. Message Retrieval Strategies

In some of the simplest aids, the user retrieves a message by finding a symbol and selecting it via his access method. This is only possible when all the vocabulary can be seen at once. In devices with a large vocabulary, not all the words can be visible at once. There has to be another way to find vocabulary items that are not immediately visible to the user. These are the message retrieval strategies.

Clinical Considerations about Selection Sets

In my experience the selection set can make or break the usefulness of a communication aid. Here are ways in which the selection set can be designed incorrectly for an individual. Keep these things in mind as you consider the options for someone:

  • the selection set vocabulary is too small for the individual's communication needs
  • the vocabulary that is initially given is too large and the individual gets lost looking for particular items
  • the individual is not gradually taught to find his way among the many symbols that he has
  • the vocabulary is disorganized, making it difficult to find items
  • the visual symbols are not clear, not immediately recognizable to the individual
  • the individual has visual impairments that make visual symbols hard to recognize
  • the auditory symbols are not clear to the individual due to a hearing impairment
  • the auditory symbols are confusing to the individual
  • the retrieval method is confusing or difficult for the individual to use
  • the individual has not been taught how to retrieve messages with this system
  • the individual has not had time to practice with this retrieval method

Some manufacturers are developing preprogrammed selection sets of some of the most complex devices. While this can be a time-saver in some cases, it can also be a mistake. Consider these factors:

  • the vocabulary will not include personal vocabulary that the individual needs (e.g. people's names, places, favorite musicians, foods, etc.)
  • the vocabulary may not be very powerful for the individual (e.g. circle time vocabulary is not nearly as powerful as vocabulary for playing a favorite game with a sibling.)
  • the symbols may not be as transparent, or clear, as they appear to those of us who can read the printed word at the top.
  • the vocabulary may be organized in a way that is confusing to the AAC user (e.g. arranged grammatically for a child who does not have a good understanding of grammar)

You can learn more about customizing vocabulary in a different section of this website.

Go back to Introduction to AAC Features
Go on to Message Composition Features