136 Advances in spoken discourse analysis
Directing and behaving form a complementary pair of moves: A asks B
to do something and B does it (or does not do it, or does something else).
We suggest however that directing and acknowledging may also form a
complementary pair: A asks B to do something, not now but later; B
acknowledges the request with a receive or an endorse, say, or perhaps
with a protest.
Exchanges
Moves combine to form exchanges: each move realizes one element of
exchange structure. There are two major classes of exchange: Organizational
and Conversational. As the table on pp. 125–7 shows, there are two subclasses
of Organizational exchange, distinguished structurally as well as functionally.
The first subclass consists of the Boundary exchange, which has only one
element of structure, Fr. The second consists of three exchanges: Structuring,
Greet and Summon, which have two obligatory elements of structure, I and
R.^1 The class of Conversational exchange consists of the following units:
Elicit, Inform, Direct, and the three bound-Elicit exchanges Clarify, Repeat
and Re-initiation. Bound-Elicit exchanges are so named because they are
bound to preceding exchanges and they all have eliciting moves at Ib. All
Conversational exchanges, with the exception of Direct (see below) have
the structure I (R/I) R (Fn), where I and R are obligatory. R/I is optional,
but it shares with R the property of being predicted, in that I predicts either
R/I (which in its turn predicts R) or just R. F is always optional and unpredicted.
Direct is the only exchange which does not have the optional element R/I,
a statement which we must ask the reader to take on trust, since to give the
reasons for this would occupy too much space.
The structure, function and realization of each unit will now be given,
with examples from either our own data or our students’. The reader will
note that the realization of R/I is not given for each exchange type: R/I is
always realized by an eliciting move (in which case R is realized by an
informing move) or by an informing move (in which case R is realized by
an acknowledging move). This is explained in full on pp. 145–9 below.
In the examples, acts are also included for the sake of completeness, ‘e.s’
stands for element of structure. Where the example is taken from our data
sample, the exchange number is given on the left.