ABSTRACT
BACKGROUND: There are a variety of graphic symbol sets/systems (GSSs) currently used in the field of augmentative and alternative communication (AAC). Various characteristics of these graphic symbol systems affect learnability and should be considered in order to make a meaningful match between the user of AAC and the system. Although a variety of studies on learnability of graphic systems have been conducted in the past, all studies conducted included participants from Western countries. AIMS: To compare two symbol systems, namely Blissymbolics and CyberGlyphs in terms of learnability. To identify the overall performance between Blissymbolics and CyberGlyphs in terms of the percentage of symbols correctly identified at the various stages. METHODS AND PROCEDURES: A quasi-experimental crossover design between groups was carried out on two homogeneous groups of typically developing, Northern Sotho-speaking children. Data were obtained by teaching 80 different referents (40 from each symbol system) to 50 Northern Sotho speaking regular students from South Africa, ranging from grade 4 to 6. The participants were tested on symbol recognition at four different stages: after initial training, after a revision period, after a 7-day withdrawal period and after 30 days of withdrawal. OUTCOMES AND RESULTS: The overall results indicated that the ease of learning and memory retention of the CyberGlyphs were higher than that of Blissymbols, irrespective of the group or the sequence of exposure. Possible reasons for the differences are discussed. CyberGlyphs seem to be more accessible as the symbols in general seem to be more detailed and also are meant to be hand drawn rather than computer or stencil produced. Within this context, CyberGlyphs could be easier to access visually than Blissymbolics, especially for children who do not have extensive experience in dealing with geometric shapes, particularly for the children who do not come from rich literacy backgrounds or who do not have rich visual perceptual experiences to draw from. CONCLUSIONS: Even though initial learning might be faster for CyberGlyphs than for Blissymbolics in certain populations, there may be other factors to consider when making a choice between the two graphic symbol systems. Within the clinical setting CyberGlyphs can provide the individual who uses AAC with a more user-friendly system as an entrance to the use of other graphic symbol systems. This may be especially important in contexts where issues surrounding poverty and lack of early exposure to literacy exist.
