Exchange structure 65which may seem all the more surprising in the light of current work in
speech act theory, pragmatics and ethnomethodology where large numbers
of different exchange initiators have been isolated. However, to see these
descriptions as necessarily in conflict is to misunderstand the nature of the
original description which, as we discussed above, spreads out complexity
along the scales of rank and delicacy.
For example the category inform includes what in many descriptions
would be distinguished as promise, prediction, statement, to name but three.
However, in order to demonstrate that these are structurally distinct units at
secondary delicacy, and not merely different semantic labels for members
of the same class, it would be necessary to demonstrate that, as well as
sharing many possible realizations for next move as is evident in (12) below,
there is also a set of possible next moves which follow them alone; it is this
crucial criterion that no one has yet been able to meet.
12 I’ll be there by eight Great
He’ll be there by eight Are you sure
I know he’ll be there by eight Just in time to eat
Eliciting exchanges
Sinclair et al. observed that in the classroom the typical eliciting exchange
was not initiation—response, IR, but rather initiation—response—feedback,
IRF, where the third part functions to evaluate and/or comment upon the
second. It is not difficult to explain the occurrence of this structure—most
teacher questions are in some sense bizarre in that the questioner usually
knows the answer already, while the answerer is himself often unsure and
thus genuinely needs to be told whether the answer he has offered is the
answer required. In many classrooms this structure is so powerful that if
there is no evaluative third part it is ‘noticeably absent’, and its absence a
clue that the answer is wrong:
13 T, I: Can you think why I changed ‘mat’ to ‘rug’?
P, R: Mat’s got two vowels in it.
T,F:Ø
T, I: Which are they? What are they?
P, R: ‘a’ and ‘t’.
T,F:Ø
T, I: Is ‘t’ a vowel?
P, R: No.
T, F: No.
While such three part exchanges typify, more than anything else, classroom
discourse, they do occur in other situations as well: