'Externalisation is a process of articulating tacit knowledge into explicit concepts. It is a quintessential knowledge- creation process in that tacit knowledge becomes explicit, taking the shapes of metaphors, analogies, concepts, hypotheses, or models. When we attempt to conceptualise an image, we express its essence mostly in language - writing is an act of converting tacit knowledge into articulable knowledge'. (Emig, 1983).
Emig, J (1983) The Web of Meaning. Upper Montclair. N.J.