The human sciences have to assume at least an equal responsibility in establishing the foundations of knowledge. - Michael Halliday

We should not, perhaps, take it for granted that a description in terms of a formalised model, which has certain properties lacking in those derived from models of another kind, will necessarily be the best description for all of the very diverse purposes for which the descriptions of languages are needed. In assessing the value of a description, it is reasonable to ask whether it has proved useful for the purposes for which it was intended.

The text is a product in the sense that it is an output, something that can be recorded and studied, having a certain construction that can be represented in systematic terms. It is a process in the sense of a continuous process of semantic choice, a movement through the network of meaning potential, with each set of choices constituting the environment for a further set.

A child learning his [her] mother tongue is learning how to name; he [she] is building up a meaning potential in respect of a limited number of social functions. These functions [instrumental, regulatory, interactional, personal, heuristic, and imaginative] constitute the semiotic environment of a very small child, and may be thought of as universals of human culture