A Study On Computational Pragmatics: Theories And Applications

Since N. Chomsky constructed the theory of Formal Language and Automaton in the fifties of the 20th century, a great progress has been made in the study of Computational Linguistics (CL). With the fast development of computer technology, the research fields of CL have extended from inputting characters to morphological analysis, syntactic parsing and semantic analysis, gradually nearing to the essence of human language. Among such fields, the analysis of language use plays a very important role, especially in Natural Language Understanding (NLU). Therefore, the study on the pragmatic interpretation and formalization of pragmatic inferences, namely Computational Pragmatics (CP), has attracted the researcher's extensive attention. Being a new branch of CL, CP study has just started from scratch. Although studies abroad have already achieved some significant fruits, most of them are dispersed in many other fields such as Linguistics, Language Philosophy, Symbolic Logic, Computer Science, and Artificial Intelligence (AI), etc. While at the domestic, except for some studies on language use in AI, comprehensive research work has almost been ignored completely. Therefore, it will be of great significance to do CP studies in both theories and applications. Some important concepts in CL study are given in brief at first, which includes Computational Linguistics (CL), Natural Language Processing (NLP), Natural Language Understanding (NLU), Computational Phonetics, Computational Lexicology and Computational Semantics, etc. In addition, the research realms and states in CL and CP both at home and abroad are summarized in brief, based on which the significance and value of this study in theory and practice are clarified explicitly. The philosophical foundations of pragmatics from the viewpoint of philosophy are set forth, including Deixis, Presupposition, Speech act theory, Conversational implicature, Relevance theory, etc, among which not only investigated deeply from the philosophical angle, but also carried on the scientific analysis from the viewpoint of linguistics. These pragmatic theories not only provide many sound interpretations for human language communication, but also bring forth new research projects for CP study. Based on the previous research work, the research aspects and states of pragmatics at home are summarized synthetically. After introducing the pragmatic development in China and the research states of Chinese pragmatics, some perspectives of Chinese pragmatics development are put forward from the viewpoint of philosophy. The latest results of research abroad should be introduced continuously, and be applied to analyze pragmatic phenomena in Chinese, from which the general pragmatic theories should be summed up to supplement current theory. The interdisciplinary development of natural and social sciences should be paid more attention to. After all, the most important thing is to do research work based on Chinese. Formal Pragmatics (FP), being originated from philosophy and logic, is one of the significant subjects in linguistics, and plays a very important role in CL as well. Therefore, some theoretical problems in FP are investigated systematically. The origin of FP is explored reasonably, the relations between FP and CP are differentiated, and the definition of CP is given in a scientific form. Also studied in this work is that an outline of Chinese formal pragmatics development is put forward, which includes to clarify the research fields of FP, to construct the independent FP theory, and to train some experts who not only grasp linguistic knowledge, but also can program computer skillfully. Approaches and methods in CP research are investigated in theory, which including the relationship between language understanding and pragmatic inference, abduction inference, reasoning about beliefs and constructing dynamic context, etc. This work will provide a new thought for the study of CP. As one of the important fields of pragmatic study, speech acts study in both theory and formalization are also explored. Austin and Searle's speech act theories are first introduced in detail, and then are evaluated from the viewpoint of Cognitive Science. Based on the theory of Situational Semantics, a pragmatic operator is given to deal with speech acts, and the pragmatic description of illocutionary act is also described formally, which provide a theoretical model for speech act interpretation in NLU system. Context plays an important role in NLU, so the formalization theory of context in Chinese Information Processing (CIP) is studied in detail. The meaning of context in modern linguistics is investigated from various points of view. Based on the comparison within the different classifications of context, a series of formal definitions about contexts are put forward, and two Chinese examples are given to illustrate the contextual constraint mechanism in NLU. A framework of NLU based on context is put forward as well. Based on the implement framework theory mentioned above, a context-based NLU model is constructed by means of SQL database technology and VC++ programming technique to verify the framework theory. The test result indicates that the correct rate of focus word meaning judgments and the understanding implicature of short sentence is 85.19% and 79.63%, respectively.