Semantic unilocality

If a language regularly places a particular closed class in syntactic construction with an open class—for example, nominal affixes with noun roots, or satellites with verbs—any conceptual category expressed by the closed class tends not to be expressed by the open class. This proposed tendency is here called “semantic unilocality”. Cognitively, semantic unilocality in language may arise from several more general tendencies, including one to avoid redundancy and one to segregate the representation of different conceptual categories. Both of these may in turn arise from a still more general tendency toward communicative efficiency. Historically, the rise, extended presence, decline, or extended absence of a closed class that expresses a particular conceptual category may foster certain diachronic processes in a syntactically associated open class. These processes include leaching, culling, shift, filtering, and abstention.