Halliday & Matthiessen (1999: 321):
Together, field, tenor and mode define the 'ecological matrix' in which particular types of text are processed: there is a systematic relationship between such matrices (particular combinations of field, tenor and mode values) and particular types of text. We can see this clearly with actual instances of text — for example, an individual recipe or weather forecast; but these are instances of general classes, to be characterised in terms of the systemic potential that is instantiated in them.That is, there is a correlation not only between a contextual matrix and a given instance of a recipe but also between that matrix and the linguistic potential that is deployed in recipes in general. This latter correlation is known as a functional variety or register of the general systemic potential.This much has been known for a long time — the notion of functional dialect was worked out by the Prague School in the 1930s (see e.g. Havranek, 1932, and Vachek, 1964), and systemic register theory has its roots in Firth's (e.g., 1957) work on restricted languages. …However, we can take one further step, as systemic theory did in the 1970s (see Halliday, 1978a), and recognise that the co-variation between context and language is not undifferentiated — it is differentiated according to the functional diversification of each of the two strata: the variables of context correlate respectively with the metafunctions of the language, field with ideational, tenor with interpersonal, and mode with textual. These pairs are mutually predictive.
Blogger Comments:
This is potentially misleading. A register is the linguistic potential that is correlated with the contextual matrix. That is, a register is not the correlation.