A Bidirectional, Transfer-Driven Machine Translation System for Spoken Dialogues

A BIDIRECTIONAL, TRANSFER-DRIVEN MACHINE TRANSLATION SYSTEM FOR SPOKEN DIALOGUES Yasuhiro SOBASHIMA, Osamu FURUSE, Susumu AKAMINE, Jun KAWAI, and Hitoshi IIDA A TR Interpreting Telecommunications Research Laboratories ABSTRACT This paper presents a brief overview of the bidirectional (Japanese and English) Transfer- Driven Machine Translation system, currently being developed at ATR. The aim of this development is to achieve bidirectional spoken dialogue translation using a new translation technique, TDMT, in which an example-based framework is fully utilized to translate the whole sentence. Although the translation coverage is presently restricted to conference registration, the system meets requirements for spoken dialogue translation, such as two-way translation, high speed, and high accuracy with robust processing. 1. INTRODUCTION Transfer-Driven Machine Translation[ll,[2],[9], (TDMT) is a translation technique which utilizes empirical transfer knowledge compiled from actual translation examples. The main part of translation is performed by the transfer module which applies the transfer knowledge to each input sentence. Other modules, such as lexical processing, analysis, and generation, cooperate with the transfer module to improve translation performance. With this transfer-centered translation mechanism together with the example- based f'ramework[3],[4].[5], which conducts distance calculations between linguistic expressions using the semantic hierarchy, TDMT performs efficient and robust translation. TDMT is especially useful for spoken language translation, since spoken language expressions tend to deviate from conventional grammars and since applications dealing with spoken languages, such as automatic telephone interpreta- tion[6],[7l,[S], need efficient and robust processing to handle diverse inputs. A prototype system of TDMT which performs bidirectional translation (Japanese to English and English to Japanese) has been implemented. This bidirectional translation system simulates the dialogues between two speakers speaking in different languages (Japanese and English) using an interpreting telephone system. Experimental results have shown TDMT to be promising for spoken dialogue translation. 2. TRANSFER-DRIVEN ARCHITECTURE The bidirectional TDMT system, shown in Figure 1, translates English into Japanese and Japanese into English. Conversion of the translation direction is simply done by flipping the mode selection switch. Moreover, all of the sharable processing modules are used in both translations. This bidirectional translation capability, along with other features adopted tbr spoken language, shows the possibility of two-way dialogue translation. The transfer module, which is the heart of the TDMT system, transfers source language expressions into target language expressions using bilingual translation knowledge. When another language-dependent processing, such as lexical processing, analysis, or generation, is necessary to obtain a proper target expression, the required module is called by the transfer module. In other words, all modules in a TDMT system function as a part of or hell) the transfer module. This transfer- centered architecture simplifies the configuration as well as the control of the machine translation system. English Terminal Japanese Terminal Fig. 1 Configuration of Bidirectional TDMT System 64 3. TRANSLATION MECHANISM 3.1 Examplc-based analysis and transfer The TDMT system utilizes an example-based framework to translate a sentence. The central mechanism of this framework it; the distance calculation[4],[5], which is measured in terms of a thesaurus hierarchy. We adopt the calculations of Sumita[51. Figure 2 shows an …

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