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MODELLING OF SHALLOW PARSING OF INDIAN LANGUAGES IIT MUMBAI April 2-4, 2006 Identification of Relative Clause as a Nominal Dependency Relation. Tanmoy Bhattacharya Nguyen Chi Duy Khuong tanmoy1@gmail.com khuongvn2000@yahoo.com Department of Linguistics University of Delhi. The Problem.
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MODELLING OF SHALLOW PARSING OF INDIAN LANGUAGESIIT MUMBAIApril 2-4, 2006Identification of Relative Clause as a Nominal Dependency Relation Tanmoy Bhattacharya Nguyen Chi Duy Khuong tanmoy1@gmail.comkhuongvn2000@yahoo.com Department of Linguistics University of Delhi MSPIL IIT Mumbai
The Problem • Implementable formalisms (e.g. HPSG) have two problems with adjuncts: • Identifying the adjunct (RECOGNITION) • Determining the place the adjunct belongs (ADDRESSING TECHNIQUE) • Solution using a “selectional” RC theory within Principles & Parameters framework MSPIL IIT Mumbai
The Solution in Brief Both the RECOGNITION and the ADDRESSING problems can be bypassed if there is no adjunct to start with: 3 The [flower that John bought] selectional relation MSPIL IIT Mumbai
The Problem in GeneralFunctor versus Argument The ARGUMENT view: Head XP COMPLEMENT The FUNCTOR view: Head XP ADJUNCT Head-Complement idea is conducive to HPSG as it is easier to see complements as semantic arguments of their heads MSPIL IIT Mumbai
The Argument View • Can explain diagnostics: • (i) Semantic Constancy: a. Sharma sleeps/ snores/ laughs in the seminar b. Sharma depends/ relies on a mouse • (ii) Iterability: Sharma opened the drawer with a key, with a hammer • (iii) Order: The police blamed the riot on the residentswithout checking the facts MSPIL IIT Mumbai
The Functor View • Cannot be imported to HPSG easily • SUBCAT cannot handle it since: • Different adjuncts attach to different heads • Not a Head-Filler semantics • Adjunct relation is syntactically different since: • Broader range of categories modified • Number of adjuncts is not pre-fixed How do we handle it then? MSPIL IIT Mumbai
Classic HPSG: The duality of representation • Pollard and Sag (1987): adjunct-main clause dependency determined by rules of grammar; specification neither on N or the RC • Assumes Type hierarchy • Rule of RC: HEAD MAJ N HEAD-DTR|SYN|LOC NFORM NORM DTRS LEX __ ADJ-DTR|SYN|RELCLAUSE MSPIL IIT Mumbai
HPSG Structure for an RC PHON solution that I like HEAD 1 SYN | LOC SUBCAT 2 LEX _ PHON solution MAJ N HEAD-DTR HEAD 1 NFORM NORM DTRS SYN|LOC SUBCAT 2 DET LEX _ PHON that I like ADJ-DTR SYN RELCLAUSE MSPIL IIT Mumbai
Problems with the Classic HPSG • A large number of such rules required • The solution rests on hierarchy of types/ subtypes (head-structure and head-adjunct-structure respectively) Phrase qo CLAUSALITY HEADEDNESS qo qo Clause non-clause hd-ph non-hd-ph • tu .. … rel-cl hd-adj-ph MSPIL IIT Mumbai
Unification • Desirable: Unification within the rule • BUT, who is selecting whom? (Functor/ Argument problem) • Functor alternative is attractive but not formalizable • So, modified heads “selecting” adjuncts (Kayne) • Every common N bearing head feature ADJUNCT • a head-adjunct rule: HEAD-DTR|SYN|LOC HEAD|ADJUNCT{..[1]..} DTRS LEX __ ADJ-DTR|SYN [1] MSPIL IIT Mumbai
HPSG schemata for solution that I like PHON solution that I like HEAD 1 SYN | LOC SUBCAT 2 LEX _ PHON solution MAJ N HEAD-DTR HEAD 1 NFORM NORM ADJUNCTS <..3..> DTRS SYN|LOC SUBCAT 2 DET LEX _ PHON that I like ADJ-DTR SYN 3 RELCLAUSE MSPIL IIT Mumbai
Revised HPSG Highest V rather than a null relativizer heads the clause: S [MOD N’] qo NP VP [MOD N’] wi NP V [MOD N’] John-I chayk-ul neh-un -nom book-acc put-rel ‘The book that John put’ Sag (1997) MSPIL IIT Mumbai
Highest V in RC need not show RC morphology Watashi ga inu ga taberu ring-o miru I NOM dog NOM eats apple-ACC see ‘I see the apple which the dog eats.’ IP 3 watashi ga I’ 3 VP I 3 NP V 3 miru CP NP 6 inuga taberu ringo • Similarly with Vietnamese MSPIL IIT Mumbai
Sag (1997) Solution who (relative) CAT NP CONT [INDEX 3] REL { 3 } QUE { } • The head words have a REL feature • Inheritance of REL is governed by WHIP MSPIL IIT Mumbai
Drawbacks of Revised HPSG • Hierarchy of types as before • Wh-relatives are wh-rel-cl and subject to a separate constraint • Subject Wh-relatives belong to yet another type and subject to yet another constraint • Non-subject relatives belong to another subtype and subject to another constraint • And so on … MSPIL IIT Mumbai
Semantics of the Gap Hunter (2004) I eat the apples which the men bought. MSPIL IIT Mumbai
Linking the two clauses MSPIL IIT Mumbai
Back to the Duality of Representation • “CP generated from the semantics of the RC is added as an adjunct to the NP.” • Doesn’t address either the RECOGNITION or the ADDRESSING problem • One feature for the RC (relativewh) and one for the MC (subclause0) Can we bypass this problem? MSPIL IIT Mumbai