The Theoretical Architecture Of Grammar

Halliday & Matthiessen (2014: 55):

The theory includes the ‘architecture’ of grammar — the dimensions that define the overall semiotic space of lexicogrammar, the relationships that inhere in these dimensions — and its relationship to other sub-systems of language — to semantics and to phonology (or graphology). Thus, according to systemic functional theory, lexicogrammar is diversified into a metafunctional spectrum, extended in delicacy from grammar to lexis, and ordered into a series of ranked units.