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<Paper uid="E91-1047">
  <Title>LIMITS OF A SENTENCE BASED PROCEDURAL APPROACH FOR ASPECT CHOICE IN GERMAN-RUSSIAN MT</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
INTRODUCTION
</SectionTitle>
    <Paragraph position="0"> Aspect is considered to bca grammatico-semanticai category for expressing various temporal references in relation to the speech act moment. Regardless of the great number of special meanings that can be expressed by the perfective or imperfectivC/ aspect (p.asp./i.asp.), there are two oppositions representing the systematic or basic aspectual meanings, namely +TOTALITY/+LIM/TEDNESS VerSus -TOTAL1TY/-LIMITEDNESS (see Bondarko 1990).</Paragraph>
    <Paragraph position="1"> In this paper we will discuss the transfer of tense and aspect, a problem which arises immediately in Machine Translation and differS from language pair to language pair. This mainly depends on how aspect is expressed in the particular languages concerned.</Paragraph>
    <Paragraph position="2"> It is obvious that aspect in several languages has a rather heterogeneous formal reflection in the verb system. Aspect and tense are closely connected with each other.</Paragraph>
    <Paragraph position="3"> In English, e.g., the two aspect constructions perfective and progressive can be seen as realizing the basic contrast of the action viewed as complete or as incomplete (for details see van Eynde 1988).</Paragraph>
    <Paragraph position="4"> All Slavic languages on the other hand have a well-formed aspect system where verbs have a perfective and an imperfectivc aspect derived from the verbal stem by affixation. The translation of verbal groups from English into Russian, for example, seems to be possible by formulating rules which assign concrete Russian aspect forms to several combinations of tense and aspect in English, e.g.</Paragraph>
    <Paragraph position="5"> has been giving (present perfect continuous) -&gt; zr~Ba/r (past, imperfective aspect) has given (present perfect) --&gt; ~ra~ (past, perfective aspect) (ef. Apresjan 1989: 154).</Paragraph>
    <Paragraph position="6"> In contrast to the languages mentioned above, aspect meaning in German, which doubtlessly exists, has no explicit formal expression. Therefore, aspect information required for translation into Russian has to be extracted from different levels of text representation. This is necessary since without the correct choice of Russian aspect serious translation errors in the target language could occur. In our German-Russian MT project VIRTEX we have approached this problem by constructing a hierarchic procedure for aspect choice (presented in the next paragraphy which takes a complex of contextual, morphological and semantical criteria into account. If the aspect choice algorithm fails to select one of the two aspect forms, wider context (beyond the bound-aries of sentence) or background knowledge must be taken into consideration. To meet this difficulty VIRTEX is provided with a system of inquiries. If necessary, human interaction is entered to make a final decision (in the sense of Personal MT, see Boitet 1990). A more perfect solution can only be reached by a more sophisticated text and knowledge representation including aspectual characteristics.</Paragraph>
    <Paragraph position="7"> - 269 -</Paragraph>
  </Section>
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