Two-Level Morphology VERSION 1.0

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1 Two-Level Morphology STEFAN LANGER, CIS UNIVERSITÄT MÜNCHEN SOMMERSEMESTER 2016 VERSION 1.0

2 Übersicht Flexionsmorphologie Ansätze zur Behandlung in der Sprachverarbeitung Two-level morphology Lexikon und Morphosyntax Two-Level-Regeln

3 Morphologische Ansätze - Beispiel bakeries -> bakery Vollformlexikon (1 Komponente) bakery.[bakery] bakeries.[bakery] Grammatik + Stammlexikon mit Varianten (2 Komponenten) bakery.[stem1,bakery] bakerie.[stem2,bakery] Word -> Stem2 + s Grammatik + Stammlexikon + Phonologischer Regeln bakery.[stem] Word -> Stem + s y becomes ie before s(plu)

4 Ansätze - Konsequenzen hyperbakeries -> hyperbakery Vollformenansatz: klappt nicht Stammvariantenlexikon + Regeln hyper.[prefix,hyper] bakery.[stem1,bakery] bakerie.[stem2,bakery] Word -> Prefix + Stem2 + 's' Two-level-Morphologie bakery.[stem] hyper.[prefix] Word -> Prefix + Stem + 's' y becomes ie before 's'

5 Motivation I Example Finnish number of word forms. Similar situation in Turkish, Hungarian and other languages lapsi N [lasten,lapseni,lapsemmekin,lapsellasi,lapsestasi,lapsenkin,lapsista,lastani, lapsetkaan,lapsellamme,lapsiinne,lapsiltani,lapsenaan,lapsistamme,lapsellemme,lapsianikaan,lapsiakin,lastanne,lapsillesi,lapsillahan,lapsinaan,lapsennekin,lapsillenikin,lapsella,lapselle,lastenne,lapsetko,lapseenkin,lapsillehan,lap sillenne,lapsillaan,lastesi,lapsistaan,lapsineen,lapsenne,lapsilla,lapselta,l apsille,lapsellensa,lapsellekaan,lapsihan,lapsiani,lapsilleen,lapsilta,lapsen,lastaan,lapsenakaan,lapsillakaan,lapset,lapsellani,lastakin,lapsiltaan,lapse stani,lapsien,lapsillakin,lapsiini,lapsethan,lapsillekaan,lapsiamme,lapsineni,lapsi,lapsillekin,lapsellanikin,lapsensakin,lapsiemme,lapsissaan,lapsilleni, lapsestamme,lapsiaankin,lapsiakaan,lapsiesi,lapsikin,lapsiltakaan,lapsina,lap sillesikin,lapsiltakin,lapsiimme,lapsellesi,lapsellanne,lapsissakin,lapseensa,lastakaan,lasteni,lapsiansa,lapsilleenkin,lapsiaan,lastensakin,lapsessani,la psistahan,lapsillasi,lapsistasi,lapsetkin,lapsistanne,lapsellenne,lastamme,la psellaan,lapsiensa,lastenhan,lapsestaan,lapsillamme,lastenkaan,lapsesi,lapsen akin,lastemme,lastasi,lasta,lapsiinsa,lapsillemme,lapselleen,lapsemme,lapsilt asi,lapsillenikaan,lapseenkaan,lapseltaan,lapseksi,lapsellakin,lapsiaankaan,l apseeni,lapsinensa,lastansa,lapsia,lapsekseen,lapsienkin,lapsiltamme,lapsenik in,lapsessa,lapseen,lapsissamme,lapsistakin,lapsiksi,lapsellekin,lapsieni,lap sistaankin,lastenko,lastensa,lapsikaan,lastenkin,lapsillensa,lapsessaan,lapsi inkin,lapsensa,lapselleni,lapsissa,lapsiin,lapsiahan,lapsianne,lapsillani,lap sistani,lapsesta,lapsiasi,lapsellako,lapsena,lapsestahan,lapsienne]

6 Motivation II Finnish proper names. Proper names are also inflected in many other languages (Polish, Russian...) porsche N [porschelta,porschella,porschessa,porschen,pors cheksi,porschelle,porscheen,porschesta,porschea,porsche]

7 Motivation III Arabic, Hebrew - Arabic and Hebrew append conjunctions, pronouns and articles to words. This leads to a very high number of different tokens which contain the same content word with any combination of affixes. والقمر wa-al-qamar and-the-moon - cannot be caught by simple dictionary lookup (dictionaries only have limited coverage) - similar phenomena are verbal clitics in romance language (e.g. Spanish)

8 Two level morphology: history Two level morphology is a model from the 80ies First presented by Kimmo Koskenniemi in 1983 Freely available implementation from the early 90ies (PCKimmo) used in some commercial systems (lingsoft)

9 Two level morphology - Komponenten 1. Wörterbuch mit Affixen und Stemmen 2. Reguläre Grammatik ins Lexikon integriert 3. Two-level-Komponente hyperbakeries hyper+ bakery+s

10 Morphotactics: Classes english.lex ALTERNATION Particle AUX AUX-V PP CJ PP-CJ DT PR DT-PR IJ ALTERNATION Prefix PREFIX ALTERNATION Root N AJ V AV N-V N-AJ AJ-V AJ-AV CD OD ALTERNATION Suffix SUFFIX ALTERNATION Infl INFL ;inflection ALTERNATION PN_Suffix PN_SUFF ;proper nouns ALTERNATION Y_Suffix Y_SUFF ;-y suffix ALTERNATION IC_Suffix IC_SUFF ;-ic suffix ALTERNATION PT_Suffix PT_SUFF ;participles ALTERNATION Clitic GEN CNTR End ALTERNATION Contraction CNTR End ;contractions ALTERNATION CD CD OD ORDR ;cardinals and ordinals ALTERNATION Compound INITIAL ;compounds ALTERNATION End End

11 extract from lexicon (affix.lex) ;LEXICON INITIAL \lf 0 \lx INITIAL \alt Particle \gl1 \gl2 \lf 0 \lx INITIAL \alt Prefix \gl1 \gl2

12 Extract from lexicon (affix.lex) ;LEXICON PREFIX \lf 0 \lx PREFIX \alt Root \gl1 \gl2 \lf hyper+ \lx PREFIX \alt Prefix \gl1 DEG3+ \gl2 DEG3+

13 Extract from lexicon (noun.lex) \lf `bakery \lx N \alt Suffix \fea deverb \gl1 `bake \gl2 #STEM with stress #STEM category #continuation #additional morph. Information \lf `balcony \lx N \alt Suffix \gl1 \gl2

14 Extract from lexicon (affix.lex) \lf 0 \lx SUFFIX \alt Infl \gl1 \gl2 ;noun plural \lf +s \lx INFL \alt Clitic \fea n/n pl reg \gl1 +PL \gl2 +PL

15 Extract from lexicon (affix.lex) ;LEXICON End ;to disable compound parsing, comment out the next entry \lf - \lx End \alt Compound \fea compound \gl1 - \gl2 \lf 0 \lx End \alt # \gl1 \gl2

16 Morphotactic rule component & lexicon Summary: - The dictionary contains affixes, stems, eventually some additional information (boundaries,stress) - simple regular grammar integrated in dictionary - operates on sequences containing morphotactic information - verifies that following are well formed sequences: Next step: hyper+`bakery+s How to we get the sequences analysed/generated by the word grammar and the lexicon from surface text? hyperbakeries? hyper+ bakery+s

17 Two level rules - Alphabet Alphabet and character classes ALPHABET ;lexical (upper) and surface (lower) characters: b c d f g h j k l m n p q r s t v w x y z a e i o u ' -. sh ch ;digraphs B C D F G H J K L M N P Q R S T V W X Y Z A E I O U ;lexical (upper) only characters: ` + NULL 0 BOUNDARY # SUBSET CN b c d f g h j k l m n p q r s t v w x y z sh ch SUBSET CNsib s x z sh ch ;sibilant consonants SUBSET CNpal c g ;palatal consonants SUBSET CNgem b d f g l m n p r s t ;geminated consonants SUBSET VO a e i o u SUBSET VObk a o u ;back vowels

18 Two level rules default mappings default mappings RULE "Defaults 1" 1 33 b c d f g h j k l m n p q r s t v w x y z sh ch a e i o u ' - ` b c d f g h j k l m n p q r s t v w x y z sh ch a e i o u ' - 0 1:

19 Two level rules types of rules => the correspondence only occurs in the environment <= the correspondence always occurs in the environment <=> the correspondence always and only occurs in the environment /<= the correspondence never occurs in the environment

20 Two level rules - examples Two level rule (always and only) ;========== ;Epenthesis ;========== ; LR: fox+s kiss+s church+s spy+s ; SR: foxes kisses churches spies RULE "+:e <=> [CNsib y:i o] s [+:@ #]" CNsib + s # y e s # i 1: : : : :

21 Two level rules - examples Two level rule (always) RULE "y:i +:@ ~[i ']" 4 y y + i i 1: : : :

22 Two level rules - examples Two level rule (only) RULE "y:i +:@ ~[i ']" 4 y + i CN i 1: :

23 Zusammenfassung Twolevel- Regeln - Regeln beschreiben systematische Beziehungen zwischen Oberflächenformen und Formen, die vom Lexikon und der Grammatik generiert werden - werden als Transducer kompiliert

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