Computers and the Humanities. Vol. 32

494 Pages·2016·2.14 MB·English

ComputersandtheHumanities 32: 1–38,1998.
1
©1998KluwerAcademicPublishers. PrintedintheNetherlands.
Tagging and the Case of Pronouns
JANNEBONDIJOHANNESSEN
TheTextLaboratory,DepartmentofLinguistics,UniversityofOslo,N-0317Oslo,Norway
(e-mail:[email protected])
Key words: Constraint Grammar, corpus investigation, nominative pronouns in English and
Norwegian,statisticinfrequency,Subjectposition
Abstract. Usingacorpustoinvestigateempiricallygrammaticalphenomenapriortowritinggram-
matical rules or constraints for a disambiguating tagger is important. The paper shows how even
casedistinctionsonpronounsareusedmorediverselythanisusuallyassumed.BothinEnglishand
NorwegiannominativepronounsareusedinmorepositionsthantheexpectedSubjectone.Although
the other uses are statistically less frequent, they may be important to the users of the resulting
taggedcorpus–whoareoftentheoreticallinguists.Ataggershouldthereforetagcorrectlyalsothe
moreinfrequentconstructions.ThepapershowshowthiscanbedoneinaConstraintGrammartype
tagger.
1. Introduction1
Tagging is often restricted to word level information such as part of speech and
morphosyntacticcategorieslikenumber,gender,caseorothertypicallyinflectional
categories. Sometaggersalsogivesyntacticfunctiontags,whichisveryusefulfor
the user of the tagged text as well as for the tagger itself – the latter being able
tousethisinformation asanaidinthedisambiguation process. Ifawordisunam-
biguousatamorphologicalaswellasasyntacticlevel,itwillbeofgreathelptothe
tagger.
Pronounsareoftenassumedtobemorphologicallyandsyntacticallyunambigu-
ous, in that they have case distinctions that correspond to syntactic distinctions.
In this paper, I shall show that pronouns can be much more ambiguous than is
often assumed. However, Ishall demonstrate that corpus investigations revealthat
different pronouns occur indifferent syntactic positions aswellasindifferent text
types. Rather than treating all pronouns alike, wecan, when designing the tagger,
make use of the fact that different pronouns differ considerably with respect to
their syntactic context. Many of the problems discussed here have been discov-
ered during our work, attheUniversity ofOslo, withdesigning aconstraint based
disambiguating taggerforNorwegian.2
The paper is structured in the following way. First some ambiguity problems
in Norwegian are discussed, and the pronominal system is given. The question of
2 JANNEBONDIJOHANNESSEN
marking the syntactic function of pronouns directly in the lexicon is introduced.
Aninvestigation ofNorwegiannominative pronouns usedinnon-Subject contexts
is presented in Section 3, and one of English nominative pronouns in Section 4.
Section 5 gives a suggestive way of tagging the various non-Subject nominatives
forNorwegian.
2. ProblemswithHomonymy
2.1. HOMONYMY IN NORWEGIAN
Whenever a word form represents several lexemes or grammatical features, a
disambiguating tagger should be able to choose between the various alternatives
andpickone.Thismeansthatthetaggerideallygivesonetagonlyperword:
(1) Anidealtagger result:
Mannenlagetbobler
“Themanmadebubbles”
Mannen <“MAN”,N,Sg,def,common,SUBJ>
laget <“MAKE”,V,pret,active>
bobler <“BUBBLE”,N,Pl,indef,common,OBJ>
In Norwegian, there is widespread homonymy between certain inflectional
forms of different Norwegian lexemes, and disambiguation can turn out to be
very difficult. Some suffixes can be used for a variety of purposes. Consider for
examplethosebelow.
(2) Twoexamplesofsuffixes thatcausewidespreadhomonymy
-er: V,presenttense (murer‘plasters’)
N,Pluralindefinite (murer‘walls’)
N,agentive (murer‘mason’)
-a: V,preterite (hoppa‘jumped’)
V,pastparticiple (hoppa‘jumped’)
N,singulardefinite (hoppa‘themare’)
N,pluraldefinite (hoppa‘thejumps’)
Therefore, manysentences aremultiplyambiguous:
TAGGINGANDTHECASEOFPRONOUNS 3
(3) Asentence withmultiplyambiguous wordforms:
Fiskerblåserbobler
Fisker (“FISHERMAN”,N,Sg,indef,common)
(“FISH”,N,Pl,indef,common)
(“FISH”,V,pres,active)
blåser (“BLOWER”,N,Sg,indef, common)
(“WHISTLE”,N,Pl,indef, common)
(“BLOW”,V,pres,active)
bobler (“BUBBLE”,N,Pl,indef, common)
(“BUBBLE”,V,pres,active)
Since Norwegian is not a free word order language, it is, fortunately, not the
case that just any combination of the three words above with just any of the tags
willactuallybeanacceptablesentence.NorwegianisaV2language,fromwhichit
followsthatinamainclause,theverbhastobeinthesecondposition(declarative
clauses)orinthefirstposition(questions). Ofallthepossibilitiesabove,theoption
of being a verb is therefore not possible for the third word - it must be a noun.
However,whichofthewordsisSubjectandwhichisObject?3 Thedisambiguating
English Constraint Grammar (ENGCG)tagger made in Helsinki for English (see,
e.g.,Karlsson etal.,1995), includes anumber ofsyntactic function labelsinaddi-
tion to the morphological tags. It is desirable for the Norwegian tagger, too, to
includesyntactic information.
In English, which is not a V2 language, it would have been easy to give the
answer: If the verb is in the second position in the clause, the noun (phrase) that
precedes it must be a Subject. A noun phrase in the first position of the clause
canonly beanalysed asafronted Objectifthere isanoun phrase following itand
thereisaverbphraseinthethirdposition:
(4) EnglishclauseswithinitialSubject andinitialfrontedObject,
respectively:
a. Fishesblowbubbles
b. Bubbles, fishesblow
Since Norwegian is a V2 language, however, there is no formal difference
betweenaclausewhichhasaSubjectinitially, andonewhichhasafrontedObject
initially. Inbothcases,thereisanounphraseoneithersideoftheverb.
4 JANNEBONDIJOHANNESSEN
(5) Norwegianclauses withinitialSubjectandinitialfronted Object,
respectively:
a. Fiskerblåserbobler
b. Boblerblåserfisker
Thedevelopers ofthe ENGCGtagger have constructed amainrule saying that
theSubjectcanbefoundjustleftofthemainverb:
(6) ThewordontheimmediateleftofthefiniteverbistheSubject.
(AdaptedfromAnttila,1995,p.321)
A similar rule is of course useless for Norwegian. We have to look for a dif-
ferent way of determining the syntactic functions of the clausal components. One
possibility isto start bytagging single wordsthat are unambiguous withregard to
both form and syntactic function. They can be helpful as cornerstones for the rest
ofthetagging.
The Finnish ENGCG tagger for the most part uses syntactic information to
determine thesyntactic category ofwordsandphrases, butsomewordshave been
assigned asyntactic category already atalexical level, i.e.,asthewords arebeing
looked up. Obviously, the earlier the tagger is able to give an unambiguous tag to
aword,thebetteritisforthedisambiguation oftherestofthewordsintheclause,
since the former ones can help ruling out a few cases. Some Norwegian function
words are unambiguous and could be syntactically marked already at a lexical
level:
(7) Somewordsthatcanbegivenasyntactic tagevenatalexical level:
at –<THAT,Sub-Conj>,introducesasubordinateclause
hvis –<IF,Sub-Conj>,introduces aconditional clause
2.2. CASE DISTINCTIONS IN PRONOUNS
It would be useful if there were a way we could tag individual words in the
lexicon in order to help us find Subjects (and thus Objects). If Norwegian were
a language that inflected its nouns for case the task would have been simple.
But, like English, nouns are invariant from a case perspective. However, also
like English, there are distinct nominative and accusative forms of some of the
personal pronouns.4 Belowisthefullparadigm ofpronouns inthebokmålversion
ofwrittenNorwegian:
TAGGINGANDTHECASEOFPRONOUNS 5
(8) Norwegianpersonal pronouns –casedistinctions
Person/Number Nominative Accusative
1Sg jeg meg
2Sg du deg
3SgM han han/ham
3SgF hun/ho henne
3SgN det det
3SgM+F,non-human den den
1Pl vi oss
2Pl dere dere
3Pl de dem
There are case distinctions in the five pairs of 1st singular, 2nd singular, 3rd
singular feminine, 1st plural, and 3rd plural pronouns. There is some individual
variation as to whether there is a case distinction in the 3Sg masculine pronoun
pair. There are no case distinctions in the 3Sg neuter, 3Sg non-human, and 2Pl
pronounpairs.Butcouldweuseatleastthefivepronominalpairsthatdohavecase
distinctions, and mark the nominative forms as Subjects and the accusative forms
asObjects?Thisquestionisworthinvestigating, butfirstweshouldnoticethatthe
3rd plural nominative pronoun has the same form as the very common definite
plural determiner. The homonymy of the pronoun and determiner de ‘they’, ‘the’
is illustrated below. Fortunately, the ambiguity between these two words is easily
resolved, sincetheyobviously occurinquitedifferentsyntactic contexts.
(9) Ambiguousde:3Plnominativepronoun or3Pldefinitedeterminer:
a. De står der borte
they stand there away
“Theyarestanding overthere.”
b. De store barna står der borte
the big children stand there away
“Thebigchildrenstandoverthere.”
2.3. LEXICAL TAGGING OF SYNTACTIC FUNCTIONS?
Ifwecouldtagpronounswithsyntacticfunctiontagsinthelexicon,alotwouldbe
gained. Although, as aclass of lexical items, pronouns are few,they are ofcourse
extremelyfrequentinmosttexts.InconstructingtheENGCGtaggerforEnglish,it
hasbeenassumedthatallnominativepronounsaresyntacticSubjectsoftheclauses
inwhichtheyoccur.SeethefollowingcitationsfromworkdiscussingtheENGCG
tagger:
6 JANNEBONDIJOHANNESSEN
(10) “Forexample,weknowthattheformshewillalwaysbeSubject,hence
thetag@SUBJmaybeincluded initslexicalentry.”
(Voutilainen, HeikkiläandAnttila,1992,p.15)
“Wordswithlexicallypredictablefunctionsinclude[...]and,crucially,
pronouns suchasheandthey,whichareSubjectbythelexicon.”
(Anttila, 1995,p.334)
Theoutputfromthemorphological analyserusedbytheENGCGtaggershows
that all the English pronouns that have nominative-accusative case distinctions
havebeengivensyntactic function labelslexically:
(11) OutputfromENGTWOL5/3-97, http://www.lingsoft.fi/cgi-pub/engtwol:
“< (cid:3)i >”
“i”<(cid:3) ><NonMod>PRONPERSNOMSG1SUBJ@SUBJ
“i”<(cid:3) >ABBRNOMSG
“<he>”
“he”<NonMod>PRONPERSMASCNOMSG3SUBJ@SUBJ
“<she>”
“she”<NonMod>PRONPERSFEMNOMSG3SUBJ@SUBJ
“<we>”
“we”<NonMod>PRONPERSNOMPL1SUBJ@SUBJ
“<they>”
“they”<NonMod>PRONPERSNOMPL3SUBJ@SUBJ
Although, undoubtedly, thismethodgivestherightresultsinmanycases, there
are some grammatical constructions in which the lexical solution gives wrong
results(theunderlining belowisdonebyJBJ):
(12) OutputfromanENGCGanalysis 5/3-97, http://www.lingsoft.fi/
cgi-pub/engcg:
a.
“<(cid:3)he>”
“he”<(cid:3)><NonMod>PRONPERSMASCNOMSG3SUBJ
@SUBJ
“<saw>”
“see”<as/SVOC/A><SVO><SV><InfComp>VPASTVFIN
@+FMAINV
“<(cid:3)john>”
“john” <(cid:3)><Proper>NNOMSG@OBJ
TAGGINGANDTHECASEOFPRONOUNS 7
“<and>”
“and”CC@CC
“<(cid:3)i>”
“i”<(cid:3) ><NonMod>PRONPERSNOMSG1SUBJ@SUBJ
“<last>”
“last”<Genord>DETPOSTSG/PL@QN>
“<night>”
“night” NNOMSG@ADVL
“<$.>”
b.5
“<(cid:3)she>”
“she”<(cid:3) ><NonMod>PRONPERSFEMNOMSG3SUBJ
@SUBJ
“<is>”
“be”<SV><SVC/N><SVC/A>VPRESSG3VFIN
@+FMAINV
“<bigger>”
“big”AcmP@PCOMPL-S
“<than>”
“than”PREP@<NOM
“<he>”
“he”<NonMod>PRONPERSMASCNOMSG3SUBJ@SUBJ
“<$.>”
3. AnInvestigation ofNominativeNon-subjectPronounsinActualTexts
Itistempting toassumethatthereisadirect correspondence betweenmorpholog-
ical case and syntactic function. This is often assumed in the linguistics literature
generally.6 However,notinfrequently, thingsaredifferentinreality–andaninves-
tigation ofactual corpora mayberevealing. Beforeattempting thelexicalsolution
for Norwegian nominative pronouns, I conducted a study of two different texts
(novels) toexamine the useofsuch pronouns. Thenovels were Gunhild byRagn-
hild Magerøy (100 000 words) and Amatøren (40 000 words) by Lars Saabye
Christensen, of which the first one is written by a female writer and set in rural
Norway, while the other is written by a male writer and set in Oslo.7 Confirm-
ing a slight suspicion, supported by some remarks in Faarlund, Lie and Vannebo
(1997)(tobecommentedonlaterinthissection),butstillsomewhatsurprisingly,it
turnedoutthatnominativepronouns areindeedusedinotherconstructions thanas
Subjectsonly. Belowisalistofconstructions inwhichnominative pronouns were
8 JANNEBONDIJOHANNESSEN
foundassomething otherthanSubject. (Abbreviations used:Gu=Gunhild, Am=
Amatøren)
A.Syntactic functions otherthanSubject:
(13) RightDislocation
a. Gunhilderdajentehoog[shetoo],[...] (Gu.)
“ButGunhildtooisagirl.”
b. Du må kjøpe deg en flaske du også [you too], hørte jeg ham (Am.)
si.
“Youhavetobuyyourself abottle,youtoo,Iheardhimsay.”
(14) LeftDislocation
a. Jeogdu[Iandyou],vibryrossitteomslarvet. (Gu.)
“Youandme,wedon’tcareaboutthegossip.”
(15) MiddleDislocation8
Ogdeterho,bareho[justshe]somfårsePålslik. (Gu.)
“Anditissheonlyshe,whogetstoseePållikethis.”
(16) Cleft
a. Det var da ikke ho som [it wasn’t she who] hadde skubbet til (Gu.)
ham,[...]
“Butitwasn’tshewhohadpushedhim...”
b. Detvardusom[itwasyouwho]ristetisengen,"saElseogså (Am.)
påmeg.
“Itwasyouwhoshookinbed,saidElseandlookedatme.”
(17) Sentence Fragment
a. E tykt e vart aldeles ålein med det. Berre e ålein. [just me (Gu.)
alone]
“IthoughtIwascompletelyalonewithit.Justmealone.”
b. Såvardetatbenamineikkevillemer. Ellerjeg[orI]. (Am.)
“Thenithappened thatmylegscouldn’t takeanymore.OrI.”
(18) Predicate
a. Erdetdu[isthatyou],Gunhild? (Gu.)
“Isthatyou,Gunhild?”
TAGGINGANDTHECASEOFPRONOUNS 9
b. Iallefall vardethan[...] (Am.)
“Atleastitwashim...”
(19) SimpleObjectandSubject-raised-to-Object
a. Herinnpåkjøkkena haresettho[she]. (Gu.)
“Hereinthekitchen Ihaveseenher.”
b. Medendelbesværfikkjegstyrthan[he]utpåkjøkkenet. (Am.)
“WithsomeeffortIwasabletoguidehimintothekitchen.”
(20) ComparativeObject
DensomharrøyntsåpassilivetsomMarjaSimensdatter, (Gu.)
oghattsåmangekarersomho[asshe],skulleletteremerke
omnoeerpåferdemellomkarogkvinnfolk
“Theonewhohasasmuchexperience inlifeasM.S.,andhadasmany
menasher,shouldeasierfeelifsomethingisgoingonbetweenman
andwoman.”
(21) Prepositional Object
[E]insetderogmeinedetsåinderlegnår’ntalavel omho[about (Gu.)
she]
“Onesitsthereandmeansitsodeeplywhenonetalksnicely
abouther.”
[Hun]varsammenmedhan[he]enstundrundtjuletider. (Am.)
“Shewasgoingoutwithhimforawhilearound Christmas.”
(22) Exclamation
Ådu,ådu[ohyouohyou],altdetudyrJonharsett. (Gu.)
“Ohmyword,allthehorrorthatJonhasseen.”
B.Pronounshomonymouswithotherpartsofspeech:
(23) Determiner(Non-pronominal use)
a. Hm-nei,mendetdimmestførhoMarit[sheMarit]no,stakkar. (Gu.)
“Mmno,butitlooksdarkerforMarit,now,poorone.”
10 JANNEBONDIJOHANNESSEN
b. Detvarhanfyren[hetheguy]medcowboystøvlene igjen. (Am.)
“Itwasthatguywiththecowboybootsagain.”
(24) Noun(Non-pronominal use)
Vierbareskyggeravvårttidligerekeg [I] (ThenewspaperAftenposten)
“Wearejustshadowsofourearlierself.”
C.Pronounsmodifiedbyotherphrases:
(25) WithRelativeclause
a. Etalaomhosom’nhagåanherpåbeit[shewhohehasgoing (Gu.)
hereongrass]
“Italkedabouttheonehekeepshere.”
b. Harduhørtomhansomikkeville[hewhodidn’twantto]tro (Am.)
påGud[...]
“Haveyourheardabouthewhodidn’t wanttobelieveinGod
...”
(26) WithPP
a. ...menmensmoragirenblankenihvaandrevil,nøyerikke (Gu.)
hopåloftet[sheonthe.loft]segmeddet.
“...butwhilethemothercouldn’t carewhatothersthink
ofone,theoneontheloftdoesnotstopitatthat.”
b. Hunmedlommetørklet[shewiththehandkerchief] ermoren (Am.)
min og han med fotografiapparatet [he with the camera] som
gårrundtpågulvet, erfarenmin,”svartejeg.
“The lady with the handkerchief is my mother and the man
with the camera who is walking around on the floor is my
father, Ireplied.”
(27) WithNP
a. Jegbegynner medatvialle[weall]erpåpakketur tiljorden (Am.)
“I’llstartwith[theidea]thatweareallonachartertour tothe
Earth.”
b. -Vimennesker[wepeople]”," ropteJakobhøyt. (Am.)
“Wehumanbeings,Jakobshouted loudly.