Il s'agit d'un réunion du réseau COST IC1207 PARSEMEThis  paper  describes  preliminary  investigationson  how  to  model  syntactic  properties  of  differ-ent types of MWEs within the framework of LFG.While there are already several works which ad-dress this topic (Attia, 2006; Asudeh et al., 2013;Patejuk,  2014),  we  are  particularly  interested  inanswering the question of which types of MWEscan be described at the level of the lexicon,  andwhich (if any) require corresponding descriptionsat the level of phrase-structure rules

Savary, Agata

Waszczuk, Jakub

Name not available

Modeling syntactic properties of MWEs in LFG

HAL Université de Tours

Modeling syntactic properties of MWEs in LFGJakub Waszczuk, Agata SavaryTo cite this version:Jakub Waszczuk, Agata Savary. Modeling syntactic properties of MWEs in LFG. Il s’agit d’unre´union du re´seau COST IC1207 PARSEME. 2015. <hal-01174660>HAL Id: hal-01174660https://hal.archives-ouvertes.fr/hal-01174660Submitted on 10 Jul 2015HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.L’archive ouverte pluridisciplinaire HAL, estdestine´e au de´poˆt et a` la diffusion de documentsscientifiques de niveau recherche, publie´s ou non,e´manant des e´tablissements d’enseignement et derecherche franc¸ais ou e´trangers, des laboratoirespublics ou prive´s.Modeling syntactic properties of MWEs in LFG [WG2]Jakub Waszczuk, Agata SavaryUniversité François-Rabelais Tours, 3 place Jean-Jaurès, 41000 Blois, France{jakub.waszczuk@etu.,agata.savary@}univ-tours.fr1 IntroductionThis paper describes preliminary investigationson how to model syntactic properties of differ-ent types of MWEs within the framework of LFG.While there are already several works which ad-dress this topic (Attia, 2006; Asudeh et al., 2013;Patejuk, 2014), we are particularly interested inanswering the question of which types of MWEscan be described at the level of the lexicon, andwhich (if any) require corresponding descriptionsat the level of phrase-structure rules.2 Structurally regular MWEsStructurally regular MWEs can be successfullyhandled by conventional grammar rules but, dueto their idiomatic meaning, should be representedas elementary language units. In contrast to ’free’structures, such expressions often adopt additionallexical and syntactic requirements, which in LFGcan be conveniently represented with f-structuresassigned to corresponding MWE descriptions.Agreement: An MWE can introduce additionalagreement constraints, as in the NP vider DET sac‘to express NP’s secret thoughts‘, lit. ‘NP emptyDET bag‘ syntactically flexible French expression,where the possessive determiner DET embeddedin the direct object of the verb vider ‘empty‘ mustagree in person and number with the subject NP(Abeillé and Schabes, 1989). Otherwise, the id-iomatic meaning is lost, e.g. ils ont vidé son sacshould be only interpreted as semantically compo-sitional ‘they have emptied his bag‘. This expres-sion can be represented by the following idiomaticdescription assigned to the verb vider:(↑ OBJ PRED FN) =c ’sac’(↑ OBJ SPEC POSS) = f (1)(f PERS) = g (f NUM) = h(↑ SUBJ PERS) = g (↑ SUBJ NUM) = hModifiers: Modification requirements can bedescribed at the level of f-structures as well. (Pate-juk, 2014) shows how to account for four types ofsuch requirements in Polish, two of which we con-sider in the description below.Syntactically flexible expression to spill thebeans ‘to reveal a secret‘ doesn’t impose any lex-ical or syntactic constraints on the kind of modi-fiers it can take. This effect can be achieved by notincluding any additional constraints (apart fromthe lexical ones and the requirement that beans oc-cur in plural, (↑ OBJ NUM) =c pl) in the func-tional description corresponding to the verb spill.The French sentential idiom NP casser sa pipe‘to die, lit. NP break his/her pipe‘ doesn’t acceptany internal modifications, just as its English ana-log to kick the bucket (both expressions are fixedand exhibit non-decomposable semantics). Thiscan be specified by requiring that the f-structurecorresponding to the verb’s object is not pairedwith any adjunct, ¬(↑ OBJ ADJUNCT).Passivization: We look at passivization as aprominent example of a syntactic transformationwhich may be blocked by MWEs, e.g. the semi-fixed expression to kick the bucket ‘to die‘. Thebucket kicked by him nominal phrase doesn’t re-tain the idiomatic meaning. This is typically thecase with opaque expressions with a completelynon-decomposable meaning.LFG posits separate active and passive verblexical entries, therefore the grammar developerneeds to make sure that the passive entry will notbe generated for the idiomatic meaning of the verbkick. This is, however, a matter related to grammardevelopment and not to the underlying formalism.3 Structurally idiosyncratic MWEsWhile structurally regular MWEs can be typicallydefined with functional descriptions at the levelof the lexicon, structurally irregular ones requirecorresponding descriptions at the level of phrase-structure rules as well.Verb-particle constructions: Verb-particleconstructions constitute a well known exampleof expressions which should not be handled byproductive grammar rules. Only specific pairs,e.g. look up ‘search for a reference‘ but notlook at (in which case at is unambiguously apreposition), can be interpreted as MWEs. Inthe English ParGram grammar this issue is han-dled by an already existing mechanism dedi-cated to subcategorization frames. The stan-dard, transitive VP rule accepts a particle ei-ther before or after the direct object of the verb(VP→V PART OBJ | V OBJ PART, in simplifiedterms), while unification over the PRT-FORM fea-ture, defined in both particle and verb lexical en-tries (e.g. (↑ PRT-FORM) = ’up’ for the particleup) guarantees that only appropriate verb-particleconstructions are recognized.A certain inelegance can be noticed in the so-lution given above. First of all, it is broken intotwo different parts and the grammar does not pro-vide any explicit evidence that the two parts are infact strongly related and describe one and the samelinguistic phenomenon. Secondly, on the level ofc-structure rules, verb-particles are treated as pro-ductive constructions, which is counter-intuitiveand does not reflect aptly their linguistic proper-ties. Finally, it shows that in LFG there is nostandard way of referring to orthographic formsor lemmas of individual MWE elements (note thatPRED is sometimes used for the same purpose).Correlative conjunctions: A similar solutionis used in LFG to model correlative conjunctionssuch as either _ or _ and both _ and _. They arehandled by a coordination rule with an optional’preconjunction’. Every preconjunction (both, ei-ther, . . . ) specifies (as a value of the COORD-FORM feature) with which conjunction it com-bines and unification guarantees that only corre-sponding pairs are recognized.Phrasal configuration: In the two aforemen-tioned cases there is no need to introduce newphrase-structure rules to handle the correspondingtypes of MWEs, but this is because appropriatemachinery (for handling subcategorization framesand coordinations, respectively) already exists.(Asudeh et al., 2013) provide an example of aSwedish traversal construction, e.g. Sarah armbå-gade sig genom mängden ‘lit. S. elbowed SELFthrough crowd.DEF‘, which is distinguished bythe requirement for the presence of a verb, a weakreflexive (coindexed with the subject), and a di-rectional PP. It also exhibits a certain word-orderpeculiarity, which can be seen in expressions con-taining verb-particles: the particle follows the di-rect object of the verb, while normally it wouldadjoin to the verb. Thus, the authors claim, thesyntactic structure of the expression can be mostelegantly modeled by a dedicated c-structure rule.In non-configurational languages MWEs mayimpose idiosyncratic preferences on the orderof their constituents. In the Polish expressiondore˛czyc´ NP do ra˛k własnych ‘deliver NP as handdelivery, lit. deliver NP to hands own‘ (Patejuk,2014), the ra˛k własnych configuration is much pre-ferred over the alternative, własnych ra˛k. More-over, the second variant can be assigned an id-iosyncratic interpretation only if it is extendedwith a possessive specifier, e.g. jego własnych ra˛k‘his own hands‘. Otherwise, własnych ‘own‘ canbe only coindexed with the subject, which contra-dicts the internal semantics of this MWE. Suchconditional word-order freezing can be modeledwith the help of an f-precedence operator, whichmakes it possible to constraint the order of individ-ual constituents (ra˛k and własnych, in this case) ofthe underlying expression (Mahowald, 2011).In another Polish expression, od przybytku NP0głowa nie boli ‘possessing a bigger quantity ofNP0 is never a problem, lit. from increase of NP0head not hurts‘, every permutation of PP (od przy-bytku NP0), NP (głowa) and VP (nie boli) is pos-sible, but the canonical PP NP VP is by far themost common one. To the best of our knowl-edge, LFG does not provide any means to defineor, more importantly, make use of such word-orderpreferences. Optimality Theory (OT) allows to de-fine preferences among concurrent configurations(Mahowald, 2011), but in OT only the optimalanalyses are preserved while all the non-optimalones are rejected during the parsing process. As aresult, the mechanism is not appropriate for mod-eling soft, quantitative preferences.Ungrammatical constructions: An idiomaticexpression all of a sudden ‘suddenly‘ has a highlyirregular structure which is not recognized by theEnglish ParGram grammar rules. This expres-sion could be modeled with a dedicated c-structurerule. However, it seems that ’ungrammatical’ con-structions of this kind are typically fixed, whichmakes them easy to handle as words-with-spacesat the preprocessing stage of the parsing process.An expression nie wszystko złoto co sie˛ s´wieci‘what seems ideal is not necessarily so, lit. noteverything gold which shines‘ lacks the verb pred-icate which is required in regular Polish sentences.The expression could be handled as word-with-spaces but, when the numerous possible expres-sions based on this phrase (nie wszystko opał co sie˛pali ‘lit. not everything combustible which burns‘,to give an example) are considered, it becomes ob-vious that a lexicalized grammar rule (S → niewszytko NP co sie˛ VP, in simplified terms) is indis-pensable to elegantly model this phrasal template.ReferencesAnne Abeillé and Yves Schabes. 1989. Parsing Id-ioms in Lexicalized TAGs. In Proceedings of theFourth Conference on European Chapter of the As-sociation for Computational Linguistics, EACL ’89,pages 1–9, Stroudsburg, PA, USA. Association forComputational Linguistics.Ash Asudeh, Mary Dalrymple, and Ida Toivonen.2013. Constructions with lexical integrity. Journalof Language Modelling, 1(1):1–54.Mohammed A. Attia. 2006. Accommodating Mul-tiword Expressions in an Arabic LFG Grammar.In Proceedings of the 5th International Conferenceon Advances in Natural Language Processing, Fin-TAL’06, pages 87–98, Berlin, Heidelberg. Springer-Verlag.Kyle Mahowald. 2011. An LFG Account of Word Or-der Freezing. In Miriam Butt and Tracy HollowayKing, editors, Proceedings of the LFG11 Confer-ence, Hong Kong, pages 381–400, Stanford, Ca.CSLI Publications.Agnieszka Patejuk. 2014. Handling MWEs in wa-lenty, a new valence dictionary for Polish. Posterpresented at the 2nd PARSEME general meeting,10–11 March, Athens, Greece.

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Modeling syntactic properties of MWEs in LFG

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