Te role of universals versus language specific grammars during acquisition is at the focal point of this study. A corpus-based investigation of two children’s harmony patterns during acquisition is carried out. It is shown that although Hebrew does not have a productive harmony grammar, there is nevertheless a considerable amount of vowel harmony in the children’s productions, suggesting speakers have a universal predisposition for such patterns. Te children start out at roughly the same point, the ultimate goal being determined by the ambient language. Te developmental paths, however, are individual. One child shows a preference for segmental considerations in determining harmony patterns, while the other shows a preference for prosodic considerations. Both children, however, gradually modify their grammars, presented herein within an Optimality Teoretic framework, ultimately reaching the same goal, an adult grammar without active vowel harmony.