This article offers a model, based on the physical conditions of articulation, for the relation between Sumerian and Akkadian stops. Other models can be discounted with a high probability. It is further argued, that the use of signs in older Akkadian should not be interpreted only from one of the two languages involved. From this point of view, a probably (if not fully provable) theory for the Akkadian š and its Sumerian counterparts is developed.