Halliday & Matthiessen (2014: 32-3):
…context extends along the cline of instantiation from the overall contextual potential of a community to the contextual instances involving particular people interacting and exchanging meanings on particular occasions. The contextual potential of a community is its culture – what we call the context of culture, following Malinowski. The context of culture is what the members of a community can mean in cultural terms; that is, we interpret culture as a system of higher-level meanings (see Halliday, 1978) – as an environment of meanings in which various semiotic systems operate, including language, paralanguage (gesture, facial expression, voice quality, timbre, tempo, and other systems of meaning accompanying language and expressed through the human body; cf. Thibault, 2004) and other human systems of meaning such as dance, drawing, painting and architecture…