There are two primary methods of representing vocabulary on a communication device and each uses pictures. The following discusses the difference between the two approaches.

Pictures
When looking at pictures as a method of coding vocabulary, it is interesting to consider the following:

1. Words can be divided into Picture Producers and Non-Picture Producers. Some words, like car, cat, house, can be represented easily by pictures. Other words like hard, fun, or healthy cannot be.

2. The vast majority of words that people use regularly are not Picture Producers. If you look at a list of the 330 most frequently occurring preschool words, you will find that only about 10% are true Picture Producers.

3. Efforts to represent Non-Picture Producing words in graphics require the use of metaphor and memory. The meaning of this picture appears obvious. It means “you.” But is it really a picture of you? No, it's a picture of a hand with a finger pointing. More appropriate meanings might be hand, finger, or point.

4. No sentence is a Picture Producer.
If representing a single word with a picture is difficult, you can imagine the difficulty representing sentences.

If pictures are to be used to represent language, then an attempt must be made to reduce the size of the symbol set. Two systems attempt to do just that, levels (multiple overlays), and semantic compaction (Minspeak).

Levels
Levels systems don’t actually reduce the size of the symbol set, but they do limit the number of pictures that the operator has to deal with at any given moment. This is done by creating communication environments and having a separate overlay for each. For example, you might have an overlay for eating, one for dressing, one for games, and one for going shopping. Whenever any of these activities takes place, the appropriate overlay is put on. This way, while the total system might have hundreds of pictures, only a small portion of them are visible at a time.

To actually talk about anything would require changing overlays to access other words. Let’s look at the following sentence: Where did she put my coat?

To get the word "where," you would need to go to the question words overlay and select the correct picture. "Did" might be found on an action word (or verb) overlay so you would have to go back to the master overlay, select the action word overlay and select the picture. "She" might be on a people (or pronoun) overlay, so it's back to the master overlay, then to the people overlay to select the picture. The same process would occur for "put" on an action word overlay, "my" on the pronoun overlay, and "coat" on a clothing overlay.

If you want the ability to put words together, to be able to converse, levels systems just don’t work very well.

Semantic Compaction (Minspeak)
Semantic Compaction also uses pictures (icons) but is actually able to reduce the size of the symbol set. It does this by assigning more than one meaning to each icon and then sequencing them together to produce those different meanings.

Each icon has a primary (picture producer) meaning and several secondary meanings. This icon certainly represents apple but can also mean red, food, or eat. Which word is generated depends on with what it is sequenced. For example, the symbol sequence

might mean red while might mean grocery.

In these examples, the first icon represents a category (colors and buildings) and the second icon represents the specific word.

Minspeak reduces the size of the symbol set permitting it to fit on a single overlay. This is crucial to effective communication because there is a link between physical action and the language it produces.

Minspeak truly does it all. It is a system that has a small symbol set yet needs only a few symbols in a sequence, it requires no literacy skills but enhances communication for people who can spell and read, it can help teach language but will never be outgrown, and it permits people to be the most effective communicators that they can be.