Halliday (2008: 49):
Thus in the interpersonal domain, the organisation of meaning into the two regions, the lexical and the grammatical, is less polarised; there is not such a clear demarcation between the general and the particular in the management of human relationships. The two contrasting perspectives are still distinct; but it becomes more apparent that the differences between them is one of depth of focus, not one of discontinuity in the phenomena themselves.