Halliday & Matthiessen (2014: 35-6):
In principle, such a taxonomy would be based on all three contextual variables – on field, tenor and mode. However, here we will present a contextual taxonomy of text that is based on field in the first instance, more specifically on the variable of socio-semiotic activity (see Matthiessen, 2006c; Matthiessen, Teruya & Lam, 2010; Teruya, 2007). … So let’s consider the nature of the socio-semiotic activity that constitutes a situation. In a sense, the activity that constitutes a situation is either one of behaviour or one of meaning; this is the traditional distinction between action and reflection. So we will make a basic distinction between activities of ‘doing’ and of ‘meaning’, and then further distinctions within ‘meaning’:
⦁ ‘doing’: the situation is constituted in some form of social behaviour, involving one or more persons. Language or other semiotic systems such as gesture, gaze and facial expression may be engaged to facilitate the performance of the activity, as when language is used to coordinate a team⦁ ‘meaning’: the situation is constituted in some process of meaning. There are seven primary types:
○ ‘expounding’: expounding knowledge about the world – about general classes of phenomena, categorising them or explaining them
○‘reporting’: reporting particular phenomena, chronicling the flow of events, surveying places or inventorying entities
○‘recreating’: recreating any aspect of prototypically human life imaginatively by dramatising or narrating events
○‘sharing’: sharing personal experiences and values, prototypically in private
○‘enabling’: enabling some course of activity, either enabling the activity by instructing people in how to undertake it or regulating the activity by controlling people’s actions
○‘recommending’: recommending some course of activity, either for the sake of the speaker through promotion of some commodity or for the sake of addressee through advice
○‘exploring’: exploring societal values and positions, prototypically in the public arena.
Note that this new addition to IFG by Halliday's reviser, Matthiessen, blurs the distinction between field ('what's going' and 'what it's about') and symbolic mode ('the rôle of language').