Shun ISHIZAKI, Shigenori TANAKA and Mutumi IMAI
Faculty of Environmental Information, Keio University
5322 Endoh, Fujisawa 252, Japan
e-mail: ishizaki@sfc.keio.ac.jp
In this study, we adopted a process view of conversational process,
according to which conversation is a two-way collaborative process,
and the linguistic unit of conversation is not a sentence but a
fragmentary and meaningful chunk. This study attempts to construct a
"grammar" of ordinary language. We believe that the grammar should
first and foremost satisfy the condition that we must be able to
express freely without being bothered by the constraint of grammatical
well-formedness. With the framework as briefed as above, we attempted
to identify the unit of chunk through analyzing conversational
data (approximately 30,000 running-word data). Last year, we suggested
that the unit of chunk be operationally defined on the basis of the
three criteria: structural, idiomatical and physical criteria.
One of the major aims of this study is to build a computational model
with a flexible mechanism for discourse understanding. Last year, we
introduced a metric space among concepts (thing concepts) in a concept
dictionary by using MDS method. A dynamic feature of such concepts'
semantics is examined by using SD method to apply the features to
metaphor analysis. This year, the following two topics are studied
for a flexible discourse understanding.
{(1) A meaning-making process in daily conversation: the role of
because}
This study emphasizes the notion of meaning-making in the analysis of
discourse in daily conversation. Tanaka and Ishizaki(1994a) suggested
that meaning is interactively produced through the mechanism of
chunking, where a chunk or an utterance unit successively triggers
another chunk, developing a stream of meaning or what is called
'discourse'. Within the framework of meaning-making. Tanaka and
Ishizaki(1994b) did a conversational analysis of the functional
role of two discourse markers, 'you know' and 'I mean'. In this study,
we focussed on because, another discourse marker. In the standard
grammar of English, because, a conjunction of subordination,
introduces a causal subordinate clause, which is governed by the main
clause. In the meaning-making process of daily conversation, however,
the main-subordinate relationship is not always clear-cut in terms of
their clause boundaries. We take it that the preceding chunk triggers
'because', with a perceived need to justify what is said. In other
words, the triggered
'because' play a functional role to provide a discourse space for the
speaker to continue. Our conversational data showed two things: (1) the
scope of 'because' is not always easy to delimit, and (2) a 'because'
clause is not always well-formed with 'structural disturbances'.
We interpreted these findings as supporting a chunking model of daily
conversation.
{(2) Dynamics of word meaning caused by context:
Interaction between verbs and objects (nouns)}
In this project, the structure of verb's polysemy is studied to obtain
the mechanism of dynamics of verb's semantics and to construct its
cognitive semantic model. The objective of this study is to use such a
mechanism and a model for constructing a concept dictionary and also
for programming algorithms of semantic analysis and conceptual analysis
of discourse. Many semantic features are listed this year to
represent dynamics of verb's semantics which interacts with that of
verb's object (noun) in a sentence. Increasing the number of verbs and
nouns (objects), the characteristics and describability of their
semantic features are studied by using cluster analysis.
Keywords: cognitive semantics semantic space, dynamics of semantics, concept dictionary, cluster analysis, SD method, chunk, adverbial clause, discourse marker, because, trigger