Machine Translation of Very Close Languages

Machine Translation of Very Close Languages Jan HAJI(~ Computer Science Dept. Johns Hopkins University 3400 N. Charles St., Baltimore, MD 21218, USA hajic@cs.jhu.edu Jan HRIC KTI MFF UK Malostransk6 nfim.25 Praha 1, Czech Republic, 11800 hric@barbora.m ff.cuni.cz Vladislav KUBON OFAL MFF UK Malostransk6 mim.25 Praha 1, Czech Republic, 11800 vk@ufal.mff.cuni.cz Abstract Using examples of the transfer-based MT system between Czech and Russian RUSLAN and the word-for-word MT system with morphological disambiguation between Czech and Slovak (~ESILKO we argue that for really close languages it is possible to obtain better translation quality by means of simpler methods. The problem of translation to a group of typologically similar languages using a pivot language is also discussed here. Introduction Although the field of machine translation has a very long history, the number of really successful systems is not very impressive. Most of the funds invested into the development of various MT systems have been wasted and have not stimulated a development of techniques which would allow to translate at least technical texts from a certain limited domain. There were, of course, exceptions, which demonstrated that under certain conditions it is possible to develop a system which will save money and efforts invested into human translation. The main reason why the field of MT has not met the expectations of sci-fi literature, but also the expectations of scientific community, is the complexity of the task itself. A successful automatic translation system requires an application of techniques from several areas of computational linguistics (morphology, syntax, semantics, discourse analysis etc.) as a necessary, but not a sufficient condition. The general opinion is that it is easier to create an MT system for a pair of related languages. In our contribution we would like to demonstrate that this assumption holds only for really very closely related languages. 1. Czech-to-Russian MT system RUSLAN 1.1 History The first attempt to verify the hypothesis that related languages are easier to translate started in mid 80s at Charles University in Prague. The project was called RUSLAN and aimed at the translation of documentation in the domain of operating systems for mainframe computers. It was developed in cooperation with the Research Institute of Mathematical Machines in Prague. At that time in former COMECON countries it was obligatory to translate any kind of documentation to such systems into Russian. The work on the Czech-to-Russian MT system RUSLAN (cf. Oliva (1989)) started in 1985. It was terminated in 1990 (with COMECON gone) for the lack of funding. 1.2 System description The system was rule-based, implemented in Colmerauer's Q-systems. It contained a full- fledged morphological and syntactic analysis of Czech, a transfer and a syntactic and morphological generation of Russian. There was almost no transfer at the beginning of the project due to the assumption that both languages are similar to the extent that does not require any transfer phase at all. This assumption turned to be wrong and several phenomena were covered by the transfer in the later stage of the project (for example …

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