Halliday & Matthiessen (1999: 381, 383):
Figure 9-4 represents the stratal organisation of the resources, diversified into field, tenor and mode (within context) and into ideational, interpersonal and textual (within the content strata of language). As we have noted, these resources are extended along the cline of instantiation from potential (language in context of culture) via subpotentials (registers in situation types) to instances (texts in contexts of situation). Figure 9-4 shows the stratified resources as being extendable along the cline of instantiation.
