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<Paper uid="P89-1007">
  <Title>GETTING AT DISCOURSE REFERENTS</Title>
  <Section position="3" start_page="0" end_page="52" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> Languages vary in the number and kinds of grammatical distinctions encoded in their nominal and pronominal systems. Language specific means for explicitly mentioning and re-mentioning discourse entities constrain what Grosz and Sidner refer to as the linguistic structure of discourse \[2\]. This in turn constrains the ways in which discourse participants can exploit linguistic structure for indicating or inferring attentional state. Attentional state, Grosz and Sidner's term for the dynamic representation of the participants' focus of attention \[2\], represents--among other thingswhich discourse entities are currently most salient. One function of attentional state is to help resolve pronominal references. English has a relatively impoverished set of definite pronouns in which gender is relevant only in the 3rd person singular, and where number---a fairly universal nominal category--is not relevant in the 2nd person. Yet even within the English pronominal system, there is a semantic contrast that provides language users with alternative means for accessing the same previously mentioned entities, therefore providing investigators of language with an opportunity to explore how distinct lexicogrammatical features correlate with distinct attentional processes. This is the contrast between demonstrative and nondemonstrative pronouns. In this paper I examine how certain uses of the singular definite pronoun it contrast with similar uses of the singular demonstrative pronoun that.</Paragraph>
    <Paragraph position="1"> I present evidence that the two pronouns it and that have pragmatically distinct contexts of use that can be characterized in terms of a remarkably simple set of preconditions. First, in SS2 1 delineate the precise nature of the comparison made here. In SS3.1, I describe the methods I used to collect and analyze a set of data drawn from ordinary conversational interactions. The result of my statistical analysis was a single, highly significant multi-dimensional distributional model, showing lexieai choice to be predicted by two features of the local context. In SS3.2, I summarize the statistical results. They were strikingly clearcut, and provide confirmation that grammatical choices made by participants in a dialogue prior to a particular point in time correlate with lexical choice of either participant at that time.</Paragraph>
    <Paragraph position="2"> Of over a dozen different variables that were examined, two alone turned out to have enormons predictive power in distinguishing between the typical contexts for the two pronouns. Very briefly, the first variable, persistence of grammatical subject, indicates whether both the antecedent and pronoun were subjects of their respective clauses. The second, persistence of grammatical form, indicates whether the antecedent was a single word phrase or a multi-word phrase, and if the latter, whether the phrase was syntactically more clause-like or more nounlike. Both variables point up the significance of the temporal dimension of discourse in two ways.</Paragraph>
    <Paragraph position="3"> The first has to do with the evanescence of surface syntactic form--the two features pertaining to the grammatical means used to refer to entities are relevant only for a short time, namely across two co-references \[17\]. The second has to do with the dual nature of referring expressions--as noted by Isard they are constrained by the prior context but immediately alter the contezt and become part of it \[3\] \[18\]. In SS4 I discuss how the contrast between the definite and demonstrative pronouns is constrained by the local discourse context, and  how the constraining features of the local context in combination with the lexical contrast provides evidence about modelling the attentional state of discourse.</Paragraph>
    <Paragraph position="4"> 2 Comparability of it and that Previous work has related the discourse deictic uses of that to the global segmental structure of discourse, and tied the contrast between it and that to the distinction between units of information introduced at the level of discourse segments versus units of information introduced at the level of the constituent structure of sentences \[8\] \[12\] \[18\]. This paper deals only with the latter category. That is, I am concerned with entities that are evoked into the discourse model by explicit mentions, i.e., noun phrases \[19\] or other intra-sentential constituents, and with the difference between accessing these referents via the definite versus the demonstrative pronoun. Thus the data reported on here are restricted to cases where one of these pronouns has occurred with an explicit linguistic antecedent that is a syntactic argument. 1 A pronoun's antecedent was taken to be a prior linguistic expression evoking (or re-evoking) a discourse entity that provided a pronoun's referent.</Paragraph>
    <Paragraph position="5"> The two expressions were not constrained to be strictly coreferential since a wide variety of semantic relationships may hold between cospecifying expressions \[I\] \[16\] \[19\].</Paragraph>
    <Paragraph position="6"> Syntactically it and that have very similar-though not identical--privileges of occurrence. 2 The following bullets briefly summarize their syntactic differences.</Paragraph>
    <Paragraph position="7">  * that, but not it, is categorially ambiguous, occurring either as a determiner or as an independent pronoun * it, but not that, has a reflexive and a possessive form ( itself/*thatsel~,, its/*thats) * it, but not that, may occur in prepositional  phrases where the pronoun in the PP corefers with a c-commanding NP (the table with a drawer in itpthat) x Pronouns whose antecedents were independent tensed clauses or clausal conjuncts were excluded from consideration here; I reported on a much larger class of contexts in t12 42;ext,. ch . mmate betw n thcm. .t _ tically occurred very rarely in my data.</Paragraph>
    <Paragraph position="8"> * it, but not that, can be used non-referentially ( it/*that is raining; it/*that is hard to find an honest politician) These differences, though they may ultimately pertain to the phenomena presented here, won't be discussed further. In general, that can occur with the same syntactic types of antecedents with which it occurs. Thus, apart from prosodic differences-which were not considered here---the two pronouns are extremely comparable semantically as well as syntactically. Both pronouns are 3rd person, nonanimate, and singular. They are thus primarily distinguished by the semantic feature of demonstrativity. null An unforeseen but interesting fact is that the proximal demonstrative this occurred very rarely.</Paragraph>
    <Paragraph position="9"> So the relevant semantic contrast was that between definiteness and demonstrativity, and did not include the proximal/non-proximal contrast associated with this versus that. While I had originally planned to investigate the contrast between the two demonstrative pronominals as well, there were only 8 tokens of this out of ,,-700 pronouns whose antecedents were sentence internal arguments. This strongly suggests that however the attentional space of discourse entities is structured, it is not as differentiated as in the spatio-temporal domain, where the contrast between this and that is apparently more relevant. With respect to the contexts examined here, the proximal/nonproximal contrast between this and that is irrelevant. null A stretch of discourse evokes a set of discourse entities, some of which can be accessed pronominally. Of these, some can be accessed by it, and some can be accessed by that. The data I present suggest that the availability of focussed entities for definite and demonstrative pronominal reference differs, and that the consequences on the subsequent attentional state also differs. The conditions on and consequences of speaker choice of it or that must be pragmatic, and further, it is likely that the choice pertains to attentional state, since both pronominaiization and demonstrativity play such a large role in indicating the attentional status of their referents (cf. \[8\], \[15\], \[18\]).</Paragraph>
    <Paragraph position="10"> The following excerpts from my conversational data illustrate the syntactic variety of the pronouns' antecedents, and give a sense as well that substituting one pronoun for another sometimes results in an equally natural sounding discourse, with the difference being a very subtle one, as  in 2. 3 Occasionally, the substitution creates discourse that is pragmatically odd, as in 6.</Paragraph>
    <Paragraph position="11">  1. A: so \[you plan to\] work for a while, save some money, travel--B: save SOME MONEY and then blow IT (/THAT) off and then go to school 2. what does NOTORIETY mean to you, where does THAT (/IT) put you 3. I didn't really want TO (PAUSE) TEACH PEO-PLE, THAT (/IT) wasn't the main focus 4. so in some ways, I'd like TO BE MY OWN BOSS, so THAT (/IT)'s something that in some way appeals to me very much 5. the drawback is THAT I'M ON CALL 24 HOURS A DAY but IT (/THAT) also means I get different periods of time off 6. I don't think EACH SITUATION IS INHERENTLY</Paragraph>
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