Please ensure Javascript is enabled for purposes of website accessibility

We only use strictly necessary cookies for this website. Please see the privacy policy for more information.   

AAC: Things to Know

Important AAC Device Features

With so many voice output devices and apps on the market today, how do you choose one?

Below is a list of features that are important for developing language skills and that address the specific challenges of autism.

  Download a PDF or view each item for an explanation.

As a child's language skills progress and there is need for new vocabulary, the language software on the device should allow for minimal motor re-learning.

If not, the automaticity that the child has developed is compromised as he has to learn a new system. This can be frustrating and discouraging when the device does not work the way it has previously.


When speaking, we put single words together in unlimited ways to express whatever’s on our mind. One of the reasons language is possible is that we "make infinite use of finite media." (Pinker, 1996)

The ASHA AAC glossary states that, "communication is based on the use of the individual words of our language. True communication is spontaneous and novel. Therefore, communication systems cannot be based significantly on pre-stored sentences."

Someone with auditory processing problems may not be able to segment their speech. That means that they may have difficulty distinguishing each word of a phrase as an individual unit.

Think of how an unfamiliar foreign language sounds to you: Can you tell where one word ends and the next begins?

The ability to use a phrase appropriately does not mean the individual understands the meaning of the individual words in that phrase. If you don't understand the words independently of each other, how will you be able to put them together in different ways to form new phrases? Being able to speak individual words allows the speaker to attach specific meaning to each word.

Core words are the most frequently occurring words. These words are dispersed throughout typical utterances; they are the glue that binds and gives meaning to the other words.

The 100 most frequently occurring words account for 60 percent of words communicated.

"For most people, about 85% of communication is accomplished using just a few hundred words." Vanderheiden, G. C, and Kelso, D. P. (1987)

Core words tend to be words that are not easily represented by a picture, so don't worry about the symbol. The symbols used on an AAC device do not have to be concrete pictures. However, their location on the device needs to be stable so that the device user can rely on motor plans for quick access.

In typical speech, our attention is directed to the conversation, not to articulating/saying the words. In order for an AAC user to develop this same "speaking" automaticity, he can't be consciously thinking about interpreting or locating icons.

For automaticity to develop, each word needs to be accessed by a unique motor plan that once learned, never changes. Two words cannot share the same motor plan.

The available vocabulary needs to be large enough to communicate wants and needs, and needs to be accessed with the least number of keystrokes. Therefore, the more icons on a screen, the better. Make the icons as small as the child can accurately access. If the amount of available icons is distracting to the child while teaching, hide the words that you are not teaching.

The ability to hide vocabulary while learning targeted vocabulary provides the opportunity to teach vocabulary while minimizing distractions yet maintaining the motor plan that will be used when all vocabulary is available.

The device should allow for changes to be made quickly with regard to what words are showing so language can be taught in natural activities. When teaching, if this hide/show process takes an excessive amount of time, the child may become distracted or lose interest.

In a language system that utilizes multi-meaning icons, the same icon will be used in different patterns to say several different words.

The picture on these icons is usually somewhat abstract, in order to convey all the meanings it represents.

Each icon does not have a one-to-one correlation with a word or a particular meaning of that word.

Multi-meaning icons are beneficial because...

  • They allow less sequencing (shorter motor plans) and enhanced rate of communication.
  • They eventually allow the individual to have a large vocabulary with hundreds or thousands of words; a single meaning icon system would need to have lots of pages which would require the cognitive skills to navigate through the system and/or much sequencing (longer motor plans).
  • A word based system paired with multi-meaning icons makes it easier to use the same icon/icon sequence to say a word to represent all the meanings of that word. For example, the word "go" has over 300 definitions; however, they can all be represented by one icon or icon sequence. There would be no need to have a different picture to represent all the meanings, or different ways to access the word based on the activity or context. Abstractness of the symbol may be a benefit when applying it to all the meanings of a word.

Once a button or series of buttons are pressed to “say” a word, the device needs to speak that word without delay. Quick association between motor movement and voice output is needed for the child to link the motor and auditory sensory input.

Also, the device should sound like a verbal speaker, in that labels of categories or pragmatic branches should not be spoken. When verbal speakers talk, they don’t think in terms of categories, pragmatic functions, or parts of speech – they just say the words that make up their thoughts.

To be a good verbal/language model, the AAC device should function similarly without speaking category labels prior to the intended word. For example, it would be very unnatural to say “I want verb play toys ball” (i.e., speaking the categories).

A complex communication system is going to contain thousands of words. To be able to support the learner, the communication partner needs to be able to quickly locate a targeted word to be able to teach the motor plan and model how to use language. A feature that will illustrate the sequence of icons that need to be touched to say a word is an essential tool, too.

Dedicated AAC Device or App?

Before the introduction of consumer tablets, the only speech generating devices available were proprietary systems manufactured by AAC device manufacturers solely for the purpose of supporting individuals with disabilities who are nonverbal.

These devices are considered durable medical equipment and therefore funded by most insurance companies and Medicaid/Medicare.

Designed to support the needs of individuals with disabilities, these devices are more expensive than an app on an iPad but can provide benefits for some individuals, including:

  • Integrated speaker amplification
  • Computer emulation
  • Warranty; repair costs covered by insurance & Medicaid
  • Free device operation and implementation training
  • Built in handle and stand
  • Accessibility options (keyguards, environmental control, scanning, eye gaze, headpointing)
  • Does not include games, educational apps so communication system is available at all times

To learn more or trial an AAC device with LAMP Words for Life, contact your PRC consultant.