With the considerable development in world wide literacy and the use of the written word, there has developed a certain prejudice against communication (of other than simple messages) by the use of images. This applies not only to communication with non-literate people but also between well-educated people from different disciplines or sectors of society without a specialized language in common.
The problem applies to all kinds and levels of teaching, but it is of particular relevance to the millions of people who can neither read nor write. Use of visual imagery (reinforced by the spoken word) provides a short cut for communicating information in areas where literacy programmes are making slow progress.
For a person to function effectively within the mainstream of modern society they must know how to read and write. To provide effective alternatives will not only discourage the development of literary skills but in doing so render millions of people and their children to third class status.