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<Paper uid="P04-3008">
  <Title>Interactive grammar development with WCDG</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> For parsing real-life natural language reliably, a grammar is required that covers most syntactic structures, but can also process input even if it contains phenomena that the grammar writer has not foreseen. Two fundamentally different ways of reaching this goal have been employed various times. One is to induce a probability model of the target language from a corpus of existing analyses and then compute the most probable structure for new input, i.e. the one that under some judiciously chosen measure is most similar to the previously seen structures. The other way is to gather linguistically motivated general rules and write a parsing system that can only create structures adhering to these rules.</Paragraph>
    <Paragraph position="1"> Where an automatically induced grammar requires large amounts of training material and the development focuses on global changes to the probability model, a handwritten grammar could in principle be developed without any corpus at all, but considerable effort is needed to nd and formulate the individual rules. If the formalism allows the ranking of grammar rules, their relative importance must also be determined. This work is usually much more cyclical in character; after grammar rules have been changed, intended and unforeseen consequences of the change must be checked, and further changes or entirely new rules are suggested by the results.</Paragraph>
    <Paragraph position="2"> We present a tool that allows a grammar writer to develop and re ne rules for natural language, parse new input, or annotate corpora, all in the same environment. Particular support is available for interactive grammar development; the effect of individual grammar rules is directly displayed, and the system explicitly explains its parsing decisions in terms of the rules written by the developer.</Paragraph>
  </Section>
class="xml-element"></Paper>