the heart of the problem: how shall we represent metaphors in wordnets? antonietta alonge, birte...

The heart of the problem:How shall we represent

metaphors in wordnets?

Antonietta Alonge, Birte Lönneker

21/01/2004 2nd GWA Conference, Brno, Czech Republic

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Preliminaries

Some examples from the Parole corpus:

• ha difeso Maastricht ed ha attaccato gli antieuropei (he/she defended Maastricht and attacked anti-

europeans)

• Mi sento tradita dalla sinistra, ora voglio lottare accanto a Berlusconi

(I feel betrayed by the left, now I want to fight together with Berlusconi)


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• gli unici che lo dipingono come il vincitore di questa guerra sono Buontempo e Alemanno

(the only ones who portray him as the winner of this war are Buontempo and Alemanno)

Wars being referred to here are arguments/discussions What is defended and attacked are claims or political

strategies

This is a normal way to refer to arguments

Preliminaries


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Cognitive Metaphor

Metaphor is not just a poetical way of speaking. Rather, it is deeply embedded in our language, culture and the way we think

Metaphoric linguistic expressions are the superficial realization of the mapping between a concrete source conceptual domain and an abstract target domain


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Consequences for lexicons

Metaphorical extension of word senses is a kind of regular polysemy:

– He arrived (‘came here’ or ‘was born’) when we were 20.

– He left us (‘went away’ or ‘died’) after some time.

Moreover:

new meanings are created by regularly exploiting and extending existing metaphors (Deignan, 1999)

There is pre-existent knowledge constraining the nature of successful novel metaphoric expressions


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Problems

Computational applications using wordnets as lexical resources may face problems with the correct interpretation of metaphoric expressions

Problems in WN/EWN

1. lack of data / inconsistency: not all the established metaphoric senses are encoded (e.g., cf. lottare in the Italian wordnet)

2. lack of structure: there is no connection among literal and related metaphoric senses and no way to connect source and target domains. Disambiguation of infrequent or novel metaphoric senses is not possible using the databases


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Metaphor encoding in EWN

Problem 1: lack of data / inconsistency

More precise and consistent information might be encoded at the synset level for established metaphoric word senses by

– Analysing corpus data– Referring to a well-established theoretical

framework such as Cognitive Metaphor theory


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Problem 2: lack of structure

Metaphoric synsets could be linked to the literal synsets they are derived from by means of a new ‘internal-relation’, e.g.:

{guerra 2} DERIVED_FROM_LITERAL {guerra 1}{attacco 8} DERIVED_FROM_LITERAL {attacco 2}

This would add more structure to the wordnets and would be useful for some applications (e.g., IR)


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How to encode information on pre-existent knowledge which constrains our possibility to produce and/or understand (infrequent or) novel metaphoric expressions? (Knowledge about conceptual domain mappings)

Representation level: higher than synset level, since this knowledge affects whole conceptual domains


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In EWN, ‘composite ILIs’ for senses related by ‘regular polysemy’ were created and used, e.g., to encode information on (possible) metonymy:

university (= building)università EQ_METONYMY

university (= organization)


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• We could create composite ILIs for metaphors as well, clustering literal and figurative synsets into coarser-grained sense groups

• All the synsets in a WN displaying a (potential) figurative sense extension would be linked to such composite ILIs and to the relevant distinctions in the TOP ONTOLOGY

{war, warfare}{dispute,…}

{fight,…}{fight, oppose…}

{war, warfare}{dispute,…}

{fight,…}{fight, oppose…}

{guerra 1} {guerra 2} XPOS_NEAR_SYNONYM

{lottare 1}

{guerra 1} {guerra 2} XPOS_NEAR_SYNONYM

{lottare 1}

AGENTIVE COMMUNICATION…AGENTIVE COMMUNICATION…

Italian WNItalian WN

ILIILI

French WNFrench WN

Dutch WNDutch WN

TOP ONTOLOGYTOP ONTOLOGY


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The End

Grazie

Danke

the heart of the problem: how shall we represent metaphors in wordnets? antonietta alonge, birte...

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