Halliday & Matthiessen (1999: 29):
We can learn about the different modes of meaning — logical, experiential, interpersonal, and textual — by exploring their different modes of representation in the grammar — chaining, constituency, prosody, and wave. Grammar is thus a hybrid system for representing meaning in the sense of embodying different modes of representation; but it is this that allows it to maintain a natural relationship with respect to semantics, with each mode of representation realising a different mode of meaning.