Tone languages provide some interesting challenges for the designers of new orthographies. One approach is to omit tone marks, just as stress is not marked in English (zero marking). Another approach is to do phonemic tone analysis, and then make heavy use of diacritic symbols to distinguish the "tonemes" (shallow marking). While orthographies based on either system have been successful, this may be thanks to our ability to manage inadequate orthographies, rather than to any intrinsic advantage which is afforded by one or the other approach. In many cases, practical experience with both kinds of orthography in sub-Saharan Africa has shown that people have not been able to attain the level of reading and writing fluency that we know to be possible for the orthographies of non-tonal languages. In some cases this can be attributed to a socio linguistic setting which does not favour vernacular literacy. In other cases, the orthography itself may be to blame. If the orthography of a tone language is difficult to use or to learn, then a good part of the reason may be that the designer either has not paid enough attention to the FUNCTION of tone in the language, or has not ensured that the information encoded in the orthography is ACCESSIBLE to the ordinary (non-linguist) user of the language. If the writing of tone is not going to continue to be a stumbling block to literacy efforts, then a fresh approach to tone orthography is required — one which assigns high priority to these two factors. This article describes the problems with orthographies that use too few or too many tone marks, and critically evaluates a wide range of creative intermediate solutions. I review the contributions made by phonology and reading theory, and provide some broad methodological principles to guide those who are seeking to represent tone in a writing system. The tone orthographies of several languages from sub-Saharan Africa are presented throughout the article, with particular emphasis on some tone languages of Cameroon.