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<Paper uid="P92-1044">
  <Title>A CCG APPROACH TO FREE WORD ORDER LANGUAGES</Title>
  <Section position="2" start_page="0" end_page="300" type="metho">
    <SectionTitle>
AN OVERVIEW OF CCGs
</SectionTitle>
    <Paragraph position="0"> In CCGs, grammatical categories are of two types: curried functors and basic categories to which the functors can apply. A category such as X/Y represents a function looking for an argument of category Y on its right and resulting in the category X. A basic category such as X serves as a shorthand for a set of syntactic and semantic features.</Paragraph>
    <Paragraph position="1"> A short set of combinatory rules serve to combine these categories while preserving a transparent relation between syntax and semantics. The application rules allow functors to combine with their arguments.</Paragraph>
    <Paragraph position="2">  In addition, egGs include composition rules to combine together two functors syntactically and semantically. If these two functors have the semantic interpretation F and G, the result of their composition has</Paragraph>
  </Section>
  <Section position="3" start_page="300" end_page="301" type="metho">
    <SectionTitle>
FREE WORD ORDER IN CCGs
</SectionTitle>
    <Paragraph position="0"/>
    <Section position="1" start_page="300" end_page="301" type="sub_section">
      <SectionTitle>
Representing Verbs:
</SectionTitle>
      <Paragraph position="0"> In this analysis, we represent both verbs and case-marked noun phrases as functors. In Karttunen's analysis (1986), although a verb is a basic element rather than a functor, its arguments are specified as subcategorization features of its basic element category. We choose to directly represent a verb's subcategorization in its functor category. An advantage of this approach is that at the end of a parse, we do not need an extra process to check if all the arguments of a verb have been found; this falls out of the combination rules.</Paragraph>
      <Paragraph position="1"> Also, certain verbs need to act as active functors in order to combine with objects without case marking.</Paragraph>
      <Paragraph position="2"> Following a suggestion of Mark Steedman, I define the verb to be an uncurried function which specifies a set of arguments that it can combine with in any order. For instance, a transitive verb looking for a nominative case noun phrase and an accusative case noun phrase has the category SI{Nn , Na}. The slash I in this function is undetermined in direction; direction is a feature which can be specified for each of the arguments, notated as an arrow above the argument, e.g. S\]{~,}. Since Turkish is not strictly verb final, most verbs will not specify the direction features of their arguments.</Paragraph>
      <Paragraph position="3"> The use of uncurried notation allows great freedom in word order among the arguments of a verb.</Paragraph>
      <Paragraph position="4"> However, we will want to use the curried notation for some functors to enforce a certain ordering among the functors' arguments. For example, object nouns or clauses without case-marking cannot scramble at all and must remain in the immediately pre-verbal position. Thus, verbs which can take a so called incorporated object will also have a curried functor category such as SI{Nn, Nd}l{~ } forcing the verb to first apply to a noun without case-marking to its immediate left before combining with the rest of its arguments.</Paragraph>
      <Paragraph position="5"> Representing Nouns: The interaction between case-marking and the ability to scramble in Turkish supports the theory that case-marked nouns act as functors. Following Steedman (1985), order-preserving type-raising rules are used to convert nouns in the grammar into functors over the verbs. The following rules are obligatorily activated in the lexicon when case-marking morphemes attach to the noun stems.</Paragraph>
      <Paragraph position="6"> Type Raising Rules:</Paragraph>
      <Paragraph position="8"> N + case ~ (vl{...}) I {v l{Ncase .... }} The first rule indicates that a noun in the presence of a case morpheme becomes a functor looking for a verb on its right; this verb is also a functor looking for the original noun with the appropriate case on its left. After the noun functor combines with the appropriam verb, the result is a functor which is looking for the remaining arguments of the verb. v is actually a variable for a verb phrase at any level, e.g. the verb of the matrix clause or the verb of an embedded clause. The notation ... is also a variable which can unify with one or more elements of a set.</Paragraph>
      <Paragraph position="9"> The second type-raising rule indicates that a case-marked noun is looking for a verb on its left. Our CCG formalism can model a strictly verb-final language by restricting the noun phrases of that language to the first type-raising rule. Since most, but not all, case-marked nouns in Turkish can occur behind the verb, certain pragmatic and semantic properties of a Turkish noun determine whether it can type-raise using either rule or is restricted to only the first rule. The Extended Rules: We can extend the combinatory rules for uncurried functions as follows. The sets indicated by braces in these rules are order-free, i.e. Y in the following rules can be any element in the set. x  Using these new rules, a verb can apply to its arguments in any order, or as in most cases, the case-marked noun phrases which are type-raised functors can apply to the appropriate verbs.</Paragraph>
      <Paragraph position="10"> Certain coordination constructions (such as SO and SOV, SOV and SO) force us to allow two type-raised noun phrases which are looking for the same verb to combine together. Since both noun phrases are functors, the application rules above do not apply. The following composition rules are proposed to allow the combining of two functors.</Paragraph>
    </Section>
  </Section>
  <Section position="4" start_page="301" end_page="302" type="metho">
    <SectionTitle>
LONG DISTANCE SCRAMBLING
</SectionTitle>
    <Paragraph position="0"> In complex Turkish sentences with clausal arguments, elements of the embedded clauses can be scrambled to positions in the main clause, i.e. long distance scrambling. Long distance scrambling appears to be no different than local scrambling as a syntactic and pragmatic operation. Generally, long distance scrambling is used to move an element into the sentence-initial topic position or to background it by moving it behind the matrix verb.</Paragraph>
    <Paragraph position="1">  (2) a.</Paragraph>
    <Paragraph position="2">  The composition rules allow noun phrases to combine regardless of whether or not they are the arguments of the same verb. The same rules allow two verbs to combine together. In the following, the semantic interpretation of a category is expressed following the syntactic category.</Paragraph>
    <Paragraph position="3"> go-nominal-acc knows.</Paragraph>
    <Paragraph position="4">  AS the two verbs combine, their arguments collapse into one argument set in the syntactic representation. However, the verbs' respective arguments are still distinct within the semantic representation of the sentence. The predicate-argument structure of the subordinate clause is embedded into the semantic representation of the matrix clause.</Paragraph>
    <Paragraph position="5"> Long distance scrambling in Turkish is quite free; however, there are many pragmatic and processing constraints. A syntactic restriction may be needed to explain why elements in certain adjunct clauses (though not all) are very hard to long distance scramble. To account for these clauses, we can assign the head of the restricted adjunct clause a curried functor category such as XIXl{argurn.ents...} rather than XI{X ,arguments...}. The curried category forces the adjunct head to combine with all of its arguments in the adjunct clause before combining with the constituent it modifies. This blocks long distance scrambling out of that adjunct clause.</Paragraph>
    <Paragraph position="6">  As mentioned before, another use for curried functions is with object nouns or clauses without case marking which are forced to remain in the immediately pre-verbal position. A matrix verb can have a category such as SI{Nn}I{S2} to allow it to combine with a subordinate clause without case-marking ($2) to its immediate left. However, to restrict a type-raised Nn from interposing in between the matrix verb and the subordinate clause, we must restrict type raised noun phrases and verbs from composing together. A language specific restriction, allowing composition only if (X ~ vl...) or (Y = vl...), is proposed, similar to the one placed on the Dutch grammar by Steedman (1985), to handle this case.</Paragraph>
  </Section>
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