The interpersonal function [of language] is the function “to establish, maintain, and specify relations between members of societies” - Michael Halliday

The text is a product in the sense that it is an output, something that can be recorded and studied, having a certain construction that can be represented in systematic terms. It is a process in the sense of a continuous process of semantic choice, a movement through the network of meaning potential, with each set of choices constituting the environment for a further set.

[Register] is set of meanings, the configuration of semantic patterns, that are typically drawn upon under the specified conditions, along with the words and structures that are used in the realization of these meanings.

It is part of the task of linguistics to describe texts, and all texts, including those prose or verse, which fall within any definition of literature and are accessible to analysis by the existing methods of linguistics.