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<Paper uid="E93-1026">
  <Title>Inheriting Verb Alternations</Title>
  <Section position="8" start_page="218" end_page="219" type="concl">
    <SectionTitle>
6 Summary and discussion
</SectionTitle>
    <Paragraph position="0"> First, HPSG-style verbal lexical entries, and the mappings between them corresponding to alternations, were described. But at this stage, the generalisations were not captured. So then these entries were translated into DATR, and arranged into a taxonomy so an alternation only needed expressing once, at a non-terminal node from which the verbs to which it applied would inherit. Information about syntax, semantics, and patterns of polysemy was concisely expressed in a manner both theoretically and computationally appealing.</Paragraph>
    <Paragraph position="1"> The lexicon fragment described in detail is part of a larger fragment which also formalises the relations holding between transitives and intransitives of 'care' verbs such as wash, where the intransitive means the same as the reflexive; between transitive, intransitive, and two ditransitive forms of the 'clear' verbs (&amp;quot;clear the desk&amp;quot;; &amp;quot;the skies cleared&amp;quot;; &amp;quot;clear the desk of papers&amp;quot;; &amp;quot;clear the papers off the desk&amp;quot;); and between transitive and ditransitive forms of 'wipe' verbs (&amp;quot;wipe the shelf&amp;quot;; &amp;quot;wipe the dust off the shelf&amp;quot;). The complete fragment thus covers a number of the common transitivity alternations of English.</Paragraph>
    <Paragraph position="2"> The paper aims to present both a study of lexical structure and an approach to practical lexicography.</Paragraph>
    <Paragraph position="3"> On the latter score, the ideal to which the paper contributes sees the lexicographer only ever needing to explicitly enter information that is idiosyncratic to a word and inheritance specifications, as everything that is predictable about a word's behaviour will be inferred. Maintaining consistency in the lexical representation, and updating and revising it, will also be quicker if a generalisation is located just at one place in the lexicon rather than at every word to which it applies.</Paragraph>
    <Paragraph position="4"> Transitivity alternations defy classification as either syntactic or semantic phenomena. They are clearly both. The generalisations are associated with semantic classes of verbs, and have both syntactic and semantic consequences. The verb taxonomy of Fig. 1 may be used for conveying specifically linguistic information, as explored in this paper, but also potentially forms part of an encyclopedic knowledge base, with knowledge about any type of cooking held at the COOKI~G-VB node and knowledge specifically about frying and baking at the Fry and Bake nodes.</Paragraph>
    <Paragraph position="5"> It might be argued that this is to confuse two different kinds of information, but, as illustrated in this paper and argued in \[Kilgarriff, 1992\], the lexicon of English holds both the syntax and semantics of lexical items. The approach offered here indicates how linguistic and encyclopedic generalisations may be attached to the same taxonomic structure.</Paragraph>
    <Paragraph position="6"> \[Boguraev and Levin, 1990\] show that an expressively adequate model for the lexicon must incorporate productive rules so that novel but rulebound uses of words can be captured. Thus &amp;quot;the her- null ring soused&amp;quot; is interpretable by any English speaker who has come across soused herring, but intransitive souse will not be added by any lexicographer to any dictionary: it is most unlikely that any corpus will provide any evidence for the form, and if it did, it would be of insufficient frequency to justify explicit treatment. The ergative form of souse must therefore be in the lexicon implicitly. Its availability to speakers and hearers of English can be inferred from knowledge of the kind of verb which souse is and the kinds of processes, or alternations, that verbs of that class can undergo. The DATR analysis demonstrates how such implicit availability of verb forms can be formalised.</Paragraph>
    <Section position="1" start_page="219" end_page="219" type="sub_section">
      <SectionTitle>
6.1 Further work
</SectionTitle>
      <Paragraph position="0"> A further question that the question of productivity invites is this: how are we to represent which verbs undergo which alternations? First, we might wish to develop devices within DATR or a related formalism for identifying which alternations apply where, and two such mechanisms are presented in \[Kilgarrift, 1992\]. But as we look closer, and consider the difficulty of placing many verbs in a semantic class, or the role of metaphor, analogy, and simple familiarity in determining which alternations are applicable in a given context of language-use, so the idea of a yes/no answer to questions of the form, &amp;quot;does this verb undergo this alternation?&amp;quot; loses plausibility.</Paragraph>
      <Paragraph position="1"> This reasoning applies also to verb classes. The analysis offers an account of verb behaviour which is premised on verb classes, but their only justification has been by appeal to commonsense and an ill-defined notion of their ability to predict which alternations a verb participates in. Nothing has been said about how the classes might be identified, or how decisions regarding where a verb should be placed might be made.</Paragraph>
      <Paragraph position="2"> The questions, &amp;quot;what class does a verb belong to?&amp;quot;, &amp;quot;what are the relative frequencies of the different patterns it occurs in?&amp;quot;, and &amp;quot;is this pattern grammaticalT' are intimately connected. Alternation behaviour is a major source of evidence as to how a verb should be classified, and grammaticality judgements are premised upon the patterns a competent speaker has frequently encountered in their experience of the language. The further development of computational lexical semantics of the kind described in this paper requires foundational work on the relation of corpus-based statistical findings to formal knowledge representation.</Paragraph>
    </Section>
  </Section>
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