Why we use symbols
Self study is an important aspect of learning. Many students who have literacy problems find research difficult. Often reference books have too much text or the layouts are too busy. These students may be able to handle ideas and information if they have to help understand the words and their meanings.
For example we have produced a variety of History books about the Romans and Greeks. There are a number of topics covered in each set and each topic book has been made at five levels. These range from books with a picture and simple text information, a text level with support for key words and new vocabulary, through levels of symbol support, to books with just a single illustrative symbol per page. In this situation, the symbols help differentiate curriculum access.