Halliday (2008: 180):
More localised features are typically intersected and construed in bundles, usually being assigned some preferred rôle in the configuration of processes: as the process itself, as a participant in the process, as quality of a participant, or as a circumstance (i.e. being assigned to an open word class — in English and Chinese, verb, noun, adjective or adverb). These open word classes construe meanings that we call “lexicalised”; and their “vectors” may be just the presence or absence of some particular component feature.