This paper concerns itself with a point in the historical phonology of Khoisan languages: what are the basic accompaniments relevant to clicks and how might the many accompaniments described for the present day languages have arisen? In order to answer this question, the whole structure of the morph has to be considered. What is presented is an outline of an approach for a historical investigation; there is no attempt to provide full descriptions, either synchronic or diachronic. The paper finally compares aspects of the sound system of Proto-Khoe with the systems of other languages in southern and eastern Africa.