52 A Grammar of Spoken English Discourse
Labov makes no predictions about either the grammatical or prosodic
form of A-events, B-events and AB-events. For him, it appears that the sole
factor determining how hearers understand speakers’ words is the concept
of shared knowledge. Labov’s category of shared knowledge includes not
only knowledge of the previous discourse but also the discourse particip-
ants’ knowledge of the roles, duties and obligations imposed upon them
by societal rules. This is similar to Brazil’s view that speakers frame their
message depending on their apprehension of the state of shared speaker/
hearer understanding. Labov’s categorization provides strong support for
Brazil’s claim that used language can be categorized into telling and asking
increments.
The categorization of speech into telling and asking increments appears
to offer a realistic insight into how people communicate with one another.
Yet, as such a categorization ultimately rests upon the concept of shared
knowledge, it is imperative that a clear and suffi cient defi nition of shared
knowledge be formulated prior to any attempt to propose a grammar such
as in Brazil (1995). The following section examines the concept of shared
knowledge.
3.2 Shared Knowledge
The term ‘shared knowledge’, which appears at fi rst glance to be intuitively
transparent, in fact proves to be nebulous. There is little agreement in the
literature as to the meaning of the terms shared and knowledge. The diffi culty
of pinning down an exact and measurable meaning led Prince (1981: 232)
to argue that as the term shared knowledge means different things to differ-
ent scholars the term itself must be abandoned prior to any investigation of
its role in discourse. Lee (2001: 22–7) in contrast attempts to reclaim the
term by re-defi ning it. He distinguishes knowledge from belief on the basis of
the relative degree of certainty held by an individual. Knowledge refers to
an individual’s 100% certainty in the truth^3 of a fact. Belief refers to a less
than 100% certainty in the truth of a fact. Mutual and shared are similarly
distinguished on the basis of certainty. Mutual indicates that the speaker is
100% certain that the hearer’s knowledge or beliefs are identical to the
speaker’s own. Shared indicates a lesser degree of certainty and is usually
based on second-hand rather than direct information. Lee defi nes common
(or background) as referring to the knowledge or beliefs two individuals share
as a result of their joint membership of a community and it is weaker than
shared. The six proposed combinations are summarized in Table 3.2.^4