Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics Introduction to Morphology Linguistics for Computer Scientists Session 4 Antske Fokkens Department of Computational Linguistics Saarland ni!ersity "# $ctober %""& uds-logo Antske Fokkens Morphology ' ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics $utline ' Introduction to Morphology Introduction *hat are morphemes+ % Subdomains of Morphology # Properties of Morphemes Morphemes and their shapes Morphological Processes 4 Morphology in Computational Linguistics Automata Finite State ,ransducers uds-logo Antske Fokkens Morphology % ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics $utline ' Introduction to Morphology Introduction *hat are morphemes+ % Subdomains of Morphology # Properties of Morphemes Morphemes and their shapes Morphological Processes 4 Morphology in Computational Linguistics Automata Finite State ,ransducers uds-logo Antske Fokkens Morphology # ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *hat is Morphology+ Morphology is the study of form and structure- In linguistics. it generally refers to the study of form and structure of /ords- uds-logo Antske Fokkens Morphology 4 ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *hat is morphology+ ,he term Morphology can refer to three different things a Description of the beha!iour of morphemes and ho/ they are combined- b Deri!ational. in0ectional and compositional processes of /ord formation occurring in a speci1c language- e-g- 23erman has a richer morphology than 4nglish5 c Description of such /ord formation processes- uds-logo Antske Fokkens Morphology 6 ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *hat are Morphemes+ Morphemes Morphemes are minimal meaning-bearing units7 e-g- talked contains t/o morphemes7 talk and -ed 8past9- Form-function pairs 8sound(sign-meaning9 :asic units of morphology Morphemes are the 2building stones5 of phrases uds-logo Antske Fokkens Morphology ) ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *hy study morphology+ 8'(%9 $ne of the main properties of language are the sound(meaning pairs *hen analy;ing language 8or learning a foreign language9. /e can<t simply list all e=pressions7 there is an in1nite number of them> So /e compose e=pressions into smaller units7 usually into phrases and /ords 8synta=9 uds-logo Antske Fokkens Morphology ? ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *hy study morphology+ 8%(%9 Can /e use /ords as basic sound(meaning units+ Problems7 ' De1nition of /ords is unclear % *ords can be composed of many components that contribute to meaning and(or grammar Se!eral applications in Computational Linguistics bene1t from morphological analysis 8more later9 uds-logo Antske Fokkens Morphology @ ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics *ords and Morphemes ,here are t/o main usages of the term word7 ' Surface form 8spoken or /ritten representation9 % Abstract form 8lemma or dictionary entry. e-g- bare in1niti!es in 4nglish. nominati!e single form of nouns in Latin9 ,he class of forms representing a /ord in different conte=ts is called a lexeme e-g- sing A Bsing, sings, sang, sung, singingC :ased on Crysmann %"") uds-logo Antske Fokkens Morphology & ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics A de1nition of /ords+ *ords can be described as units of language 8either seDuences of sounds. or signs9 that function as meaning bearers- :ut this is a fu;;y notion. e-g-7 talked in she talked e=presses both 2talking5 and past tense- Is more or less one /ord. or are there three /ords+ A structuralist solution7 morphemes uds-logo Antske Fokkens Morphology '" ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics A language7 ''-''% phonemes ↓ 4."""-'".""" morphemes ↓ uds-logo An in1nite number of sentences Antske Fokkens Morphology '' ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics Morphs and Morphological Analysis ,he realisations of morphemes are called morphs7 e-g- 4nglish plural morpheme7 [E M:4F pl]7 -s. -es. -en. -∅ boy-s. bo=-es. o=-en. sheep ,hese different realisations of the same morpheme are called allomorphs- Morphological analysis Segmentation of e=pressions into basic units 8mostly starting from /ord-le!el9- Classi1cation of these basic units according to function- :ased on Crysmann %"") uds-logo Antske Fokkens Morphology '% ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics ,ypes of morphemes Free Morphemes Free morphemes can occur independently- Free morphemes are common in both 4nglish and 3erman- e-g- boy. sing Bound Morphemes :ound morphemes must be attached to another morpheme. and cannot be used independently- e-g- [E M:4F pl] -s → boys :ased on Crysmann %"") uds-logo Antske Fokkens Morphology '# ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics ,ypes of bound morphemes ,ypical bound morphemes are7 affixes 8boy+s. talk+ed9 clitics 8French7 je ne sais pas. je and ne cannot occur /ithout a !erb9 roots 8Spanish habl- needs an ending indicating person. number. mode. etc-9 uds-logo Antske Fokkens Morphology '4 ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics Formati!es Morphemes are form-meaning pairs. but not all segmental forms ha!e an identi1able meaning7 Formatives are forms /ithout identi1able meaning e-g- Linking elements in 3erman compounds7 Geburt+s+tag 8:irthday9. Schwan+en+hals 8s/an neck9- :ased on Crysmann %"") uds-logo Antske Fokkens Morphology '6 ( )& Introduction to Morphology Subdomains of Morphology Introduction Properties of Morphemes *hat are morphemes+ Morphology in Computational Linguistics Pseudo Morphemes Pseudo-morphemes or cranberry morphemes are special cases of formati!es- ,hey are segment-able part of a comple= /ord. but do not ha!e an independent meaning7 e-g- cran+berry. rasp+berry re+ceive. con+ceive :ased on Crysmann %"") uds-logo Antske Fokkens Morphology ') ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics $utline ' Introduction to Morphology Introduction *hat are morphemes+ % Subdomains of Morphology # Properties of Morphemes Morphemes and their shapes Morphological Processes 4 Morphology in Computational Linguistics Automata Finite State ,ransducers uds-logo Antske Fokkens Morphology '? ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics Areas of Morphology *e distinguish7 Word forming7 Deri!ational morphology Compounding Inflection uds-logo Antske Fokkens Morphology '@ ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics Deri!ational Morphology allo/s to build comple= /ords by combining bound and free morphemes- Deri!ational operations are per de1nition optional. i-e- not reDuired by syntactic criteria- uds-logo Antske Fokkens Morphology '& ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics Changes made by deri!ational morphemes 8a9 semantics. e-g- GclearH → GunIGclearHH A unclear 8b9 syntactic category. e-g- GderiveHV → GGGderiveHV IationHN IalHAdj A deri!ational 8c9 !alency of a !erb. e-g- G awH <it breaks< → GtIG awHH <he breaks it< 8Ja!asupai9 8d9 se!eral from the abo!e. e-g- GunderstandHV → GGunderstandHV IableH A understandable uds-logo Antske Fokkens Morphology %" ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics Compounding allo/s to build comple= /ords by Ku=taposition of free morphemes- [GsaleHIsIGmanH]. GGdishHIGwasherHH- Producti!e compounding results in an in1nite le=icon- !nglish phonetics teacher 8 98 98 9 <German =<phonology =<researcher= "avasupai morphology student : ;: ;: ; :ased on Crysmann %"") uds-logo Antske Fokkens Morphology %' ( )& Introduction to Morphology Subdomains of Morphology Properties of Morphemes Morphology in Computational Linguistics In0ectional Morphology 8'(%9 In0ection is reDuired by syntactic criteria. e-g- an 4nglish !erb must ha!e tense- It marks grammatical 8Amorpho-syntactic9 distinctions7 ConKugation 8!erbal categories97 ' person. number. gender %