Variation in lexicogrammar across varieties of English is, of course, not only qualitative but also quantitative; the system of lexicogrammar is probabilistic in nature, and probabilities vary across varieties of English – dialectal, codal and registerial varieties.
In general, like any other language, English needs to be interpreted and described as an assemblage of varieties — varieties that are differentiated along different dimensions, with fuzzy boundaries. Thus, English is subject to dialectal, codal and registerial variation, each type of variation having a different locus within the strata of the language and covering a different range along the cline of instantiation.
This introduction to (systemic) functional grammar differs in various ways from other accounts — in terms of both theory and description. … (ii) In terms of description, this book is of course an introduction to a systemic functional description of the grammar of English — constituting one descriptive strand evolving among other ones in systemic functional linguistics. This description may be compared with other descriptions of the grammar of English that have appeared over the past 500 years or so. These descriptions naturally vary in many ways, e.g.
- relationship to theory (homogenous or heterogeneous [‘eclectic’]),
- relationship to corpus, relationship to time (diachronic vs. synchronic, or some kind of synthesis),
- relationship to dialectal variation (what varieties of English are included),
- coverage of phenomena — from grammars of very selective coverage via grammars with a registerial focus (such as grammars of spoken English) to reference grammars, and
- relationship to intended users — ranging from language learners to professional grammarians.
Reference grammars are, in principle, the most comprehensive descriptions.
Whereas dialect variation was variation according to the user, register variation was variation according to the use. Like dialect, register was the name of a kind of variation; so if we talk of “a register”, this is again analogous to “a dialect”, in the sense that each refers to a clustering of features that typically go together. In the case of register, these will be explained in terms of the view from above — the context of situation [i.e. context as instance] and the context of culture [i.e. context as system]. In other words, a pattern of regularities in this middle range of generality (pertaining to less than the language but more than the individual text) is most clearly observed from the “system” position, where it will appear as a motivated resetting of the global probabilities of the language.
It is particularly in accounting for different kinds of variation in language — dialect, register and genre, Bernstein’s “code” — that the complementarity becomes important for our understanding; and especially in overcoming those unfortunate disjunctions that we have come to live with, that between linguistics and pragmatics at one level, and that between theory of grammar and theory of discourse at another.