GEOMETRY OF TRAIT COOCCURRENCE RESTRICTIONS IN SEMITIC AND BERBER - SYNCHRONY AND DIACHRONY

The main goal of this article is to provide a more global approach to the question of cooccurrence restrictions which hold among classes of segments in Hamito-Semitic languages. It is demonstrated that the Obligatory Contour Principle (OCP) combined with the directionality conventions is not sufficient to predict all of the observed cooccurrence restrictions found in the Classical Arabic verb root and that it is necessary to postulate two other constraints that interact with the OCP. By establishing a parallel between the facts observed in Classical Arabic and the labial dissimilations in two other Hamito-Semitic languages, Akkadian and Imdlawn Tashlhiyt Berber, it is argued that, at the Proto-Hamito-Semitic stage, the OCP hierarchically dominated the Multiple Association Constraint operative at the level of articulator nodes, but that this hierarchy is no longer synchronically manifested in languages like Arabic and Hebrew. The existence of a constraint that imposes a minimal sonority distance on rising sonority contours is also postulated to account for an asymmetry indicating a tendency to prefer certain sequences of segments over the reverse order.