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<Paper uid="W05-0509">
  <Title>subject/object learning</Title>
  <Section position="4" start_page="72" end_page="73" type="intro">
    <SectionTitle>
2 Subjects and Objects in Italian
</SectionTitle>
    <Paragraph position="0"> Children that learn how to process subjects and objects in Italian are confronted with a twofold challenge: i) the relatively free order of Italian sentence constituents and ii) the possible absence of an overt subject. The existence of a preferred Sub-ject Verb Object (SVO ) order in Italian main clauses does not rule out all other possible permutations of these units: in fact, they are all attested, albeit with considerable differences in distribution and degree of markedness (Bartolini et al. 2004).1 Moreover, because of pro-drop, an Italian Verb Noun (VN) sequence can either be interpreted as a VO construction with subject omission (e.g. ha dichiarato guerra '(he) declared war') or as an instance of postverbal subject (VS, e.g. ha dichiarato Giovanni 'John declared'). Symmetrically, an NV sequence is potentially ambiguous between SV and OV: compare il bambino ha mangiato 'the child ate' with il gelato ha mangiato 'the ice-cream, (he) ate'.</Paragraph>
    <Paragraph position="1"> These grammatical facts are in keeping with what we know about Italian children's parsing strategies. Bates et al. (1984) show that while, in English, word order is by and large the most effective cue for subject-object identification (henceforth SOI) both in syntactic processing and during the child's syntactic development, the same cue plays second fiddle in Italian. Bates and colleagues bring empirical evidence supporting the hypothesis that Italian children show extreme reliance on NV agreement and, secondly, on noun animacy, rather than word order. They conclude that the follo w ing syntactic constraints dominance hierarchy is operative in Italian: agreement &gt; animacy &gt; word order. The fact that animacy can reliably be resorted to in Italian SOI receives indirect confirmation from corpus data. We looked at the distribution of animate subjects and objects in the Italian Syntactic Semantic Treebank (ISST, Montemagni et al., 2003), a 300,000 tokens syntactically annotated corpus, including articles from contemporary Ita lian newspapers and periodicals covering a broad variety of topics. Subjects and objects in ISST were automatically annotated for animacy using the SIMPLE Italian computational lexicon (Lenci et al. 2000) as a background semantic resource.</Paragraph>
    <Paragraph position="2"> The annotation was then checked manually. Corpus analysis highlights a strong asymmetry in the distribution of animate nouns in subject and object roles: over 56.6% of ISST subjects are animate (out of a total number of 12,646), while only the 11.1% of objects are animate (out of a total number of 5,559). Such an overwhelming preference for inanimate ob jects in adult language data makes animacy play a very important role in SOI, both as a key developmental factor in the bootstrapping of the syntax-semantics mapping and as a reliable  processing cue, consistently with psycholinguistic data.</Paragraph>
    <Paragraph position="3"> On the other ha nd, the distribution of word order configurations in the same corpus shows another interesting asymmetry. NV sequences receive an SV interpretation in 95.6% of the cases, and an object interpretation in the remaining 4.4% (most of which are clitic and relative pronouns, whose preverbal pos ition is grammatically constrained).</Paragraph>
    <Paragraph position="4"> The situation is quite different when we turn to VN sequences, where verb-object pairs represent 73.4% of the cases, with verb-subject pairs representing the remaining 26.6%. We infer that - at least in standard written Italian - VS is a much more consistently used construction than OV, and that the role of word order in Italian parsing is not a marginal one across the board, but rather relative to VN contexts only. In NV constructions there is a strong preference for a subject interpretation, and this suggests a more dynamic dominance hierarchy of Italian syntactic constraints than the one provided above.</Paragraph>
    <Paragraph position="5"> As for agreement, it represents conclusive evidence for SOI only when a nominal constit uent and a verb do not agree in number and/or person (as in leggono il libro '(they) read the book'). On the contrary, when noun and verb share the same per-son and number the impact of agreement on SOI is neutralised, as in il bambino legge il libro 'the child reads the book' or in ha dichiarato il presidente 'the president declared'. Although this ambiguity arises in specific contexts (i.e. when the verb is used in the third person singular or plural and the subject/object candidate agrees with it), it is interesting to note that in ISST: third person verb forms cover 95.6% of all finite verb forms; and, more interestingly for our present concerns, 87.9% of all VN and NV pairs involving a third person verb form contains an agreeing noun. From this we conclude that the contribution of agreement to our problem is fairly limited, as lack of agreement shows up only in a limited number of contexts.</Paragraph>
    <Paragraph position="6"> All in all, corpus data lend support to the idea that in Italian SOI is governed by a complex interplay of proba bilistic constraints of a different nature (morpho-syntactic, semantic, word order etc.).</Paragraph>
    <Paragraph position="7"> Moreover, distributional asymmetries in la nguage data seem to provide a fairly reliable statistical basis upon which relevant probabilistic constraints can be bootstrapped and combined consistently. In the following section we shall present a ME model of how constraints and their interaction can be bootstrapped from la nguage data.</Paragraph>
  </Section>
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