What we are referring to as ʻsocial contextʼ is a generalized type of situation that is itself significant in terms of the categories and concepts of some social theory. The theory may focus attention on different facets of the social structure: not only on forms of socialization and cultural transmission, but also on role relationships, on the power structure and patterns of social control, on symbolic system, systems of values, of public knowledge and the like.
- Halliday (1973), a pag.63

It is the social context that defines the limits of the options available; the behavioural alternatives are to this extent context-specific.
- Halliday (1973), a pag.64

In the sociological context, the relevant extra-linguistic elements are the behaviour patterns that find expression in language. It is convenient to treat these under two headings: social, and situational. First, there are the specifically social aspects of language use: the establishment and maintenance of the individual’s social roles, the establishment of familiarity and distance, various forms of boundary maintenance, types of personal interaction and so on. These are largely indipendent of setting, but relate to generalized social contexts, such as those of mother and child already referred to.
- Halliday (1973), a pag.79