Ronald Langacker - Trees, Assemblies, Chains, and Windows

For describing grammatical organization, metaphors based on a variety of source domains—including trees, networks, chains, paths, and windows—all appear to have some validity. In Cognitive Grammar they pertain to facets of assemblies, where semantic and phonological structures are connected by relations of symbolization, composition, and categorization. Assemblies have a temporal dimension; consisting in sequenced processing activity that runs concurrently on different time scales, they involve both seriality and hierarchy. In their hierarchical aspect, they are comparable to constituency trees, and in their connections, to dependency trees. Assembly elements, which can be characterized at any level of specificity, are connected in both syntagmatic and paradigmatic relations. A person’s linguistic ability comprises a vast assembly of conventional units, a portion of which are activated as part of the transient assembly constituting a particular expression. Lexicon and grammar effect the implementation of semantic functions—affective, interactive, descriptive, and discursive—which emerge with varying degrees of salience depending on their symbolization by segmental, prosodic, and other means. Assemblies thus make possible a unified approach to processing, structure, function, and use.