Halliday (1984, 1985a:
68-71) approaches the grammar of interaction from semantic perspective. He
points out that whenever we use language to interact, one of things we are
doing with it is establishing a relationship between us: between the person
speaking now and the person who will probably speak next.
The mood structure of the clauses refers to
the organization of asset of functional constituents including the constituent
Subject. The component that gets bandied back and forth is what we call the
MOOD element of the clause (we use capital letters to differentiate the MOOD
constituent of the clause from the general term, Mood, which describes the
overall structure of the clause) The other component is called the RESIDUE. We
can already, then suggest thet propositions can be divided into two functional
constituent.
We have therefore
identified two essential functional constituents of the MOOD component of the
clause: the Subject and the Finite. the Subject offered by Halliday (1985a: 76)
is that it realizes the thing by reference to which the proposition can be
affirmed denied. It provides the person or thing in whom is vested the success
or failure of the proposition, what is “held responsible”. The second
constituent of MOOD element is the Finite. Halliday (1985a: 75) defines the
Finite in terms of its function in the clause to make the proposition definite,
to anchor the proposition in a way that we can argue about it.