One of the key aspects of Systemic Functional Linguistics for EFL teaching is the notion of the language as an exchange, that “the clause is organised as an interactive event” (H & M, p.106). At a semantic level, language simultaneously operates through a system of three speech-act functions:
- Move – initiating or responding;
- Role – giving or demanding, and;
- Commodity – information or goods & services.
This is the fundamental system of exchange in language. The importance of this for EFL is that all the seemingly infinite number of social functions of language we might initiate, such as requesting something or borrowing a pen or giving instructions, may in fact be reducible to just two combinations of role and commodity:
- Giving information – It’s a pen.
- Demanding information – What is it?/ Is it a pen?
- Demanding goods & services – Give me a pen!
- Giving goods & services – Would you like a pen?
Essentially, everything within the clause is semantically related to one of these four functions. We may want to expand this with regards to how sure we are (Admittedly, it almost certainly must not be a pen) but it is still just giving information.