JETR: A Robust Machine Translation System

JETR: A ROBUST MACHINE TRANSLATION SYSTEM Rika Yoshii Department of Information and Computer Science University of California, Irvine, Irvine, California, 92717 t ABSTRACT This paper presents an expectation-based Japanese- to-English translation system called JETR which relies on the forward expectation-refinement process to handle ungrammatical sentences in an elegant and efficient manner without relying on the presence of particles and verbs in the source text. JETR uses a chain of result states to perform context analysis for resolving pronoun and object references and filling ellipses. Unlike other knowledge-based systems, JETR attempts to achieve semantic, pragmatic, structural and lexical invariance. INTRODUCTION Recently there has been a revitalized interest in machine translation as both a practical engineering problem and a tool to test various Artificial Intelligence (AI) theories. As a result of increased international communication, there exists today a massive Japanese effort in machine translation. However, systems ready for commercialization are still concentrating on syntactic information and are unable to translate syntactically obscure but meaningful sentences. Moreover, many of these systems do not perform context analysis and thus cannot fill ellipses or resolve pronoun references. Knowledge-based systems, on the other hand, tend to discard the syntax of the source text and thus are unable to preserve the syntactic style of the source text. Moreover, these systems concentrate on understanding and thus do not preserve the semantic content of the source text. An expectation-based approach to "Japanese-to- English machine translation is presented. The approach is demonstrated by the JETR system which is designed to translate recipes and instruction booklets. Unlike other Japanese-to-English translation systems, which rely on the presence of particles and main verbs in the source text (AAT 1984, Ibuki 1983, Nitta 1982, tThe author is now located at: Rockwell International Corp. Autonetics Strategic Systems Division Mail Code: GA42 3370 Miraloma Avenue, P.O. Box 4192 Anaheim, California 92803-4192 Saino 1983, Shimazu 1983), JETR is designed to translate ungrammatical and abbreviated sentences using semantic and contextual information. Unlike other knowledge-based translation systems (Cullingford 1976, Ishizaki 1983, Schank 1982, Yang 1981), JETR does not view machine translation as a paraphrasing problem. JETR attempts to achieve semantic, pragmatic, structural and lexical invariance which (Carbonell 1981) gives as multiple dimensions of quality in the translation process. Sends phrases, wood d~sses and phrase roles [Analyzer[ (PDA) ,~ Sends object frames Sends object framms and action frames Sends modified expectations, modified object types and filled frames Generator I Resolves Sends an~hofic object references frames I Context Analyzer I Figure 1. JETR Components JETR is comprised of three interleaved components: the particle-driven analyzer, the generator, and the context analyzer as shown in Figure 1. The three components interact with one another to preserve information contained in grammatical as well as ungrammatical texts. The overview of each component is presented below. This paper focuses on the particle- driven analyzer. CIIARACTERISTICS OF TilE JAPANESE LANGUAGE The difficulty of translation depends on the similarity between the languages involved. Japanese and English are vastly different languages. Translation from Japanese to English involves restructuring of …

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