Morphology For Marathi POS-Tagger Veena Dixit 11/ 10 /2005

Contents Word Morphology Marathi Morphology - definition of the task and difficulties thereto. Marathi Morphology - solutions to the challenges Different word classes Postpositions Particles Interjections Conjunctions Pronouns Adjectives Adverbs Verbs Nouns

Words are the orthographical strings separated by spaces and some punctuation marks. To syntax, words make sentences and to morphology, word has internal structure and has different inflectional forms. Inflectional forms of a root word form a paradigm based on a principle. Root word is the form which is stored in lexicons / dictionaries.

What is Morphology? Morphology is the study of forms of words in the language, especially the different forms used in declensions, conjugations, and word building. It deals with the morphemes. Morpheme is a term which refers to the smallest component of a word that (a) seems to contribute some sort of meaning, or a grammatical function to the word to which it belongs, and (b) cannot be decomposed into smaller morphemes.

Marathi Morphology Definition of the task and difficulties thereto Morphological analysis of Marathi plays significant role in natural language processing because Marathi, a pan Indian Language, is rich in morphology. Marathi, being the language of the area situated centrally, gets influenced by almost all language groups of India. This makes the Marathi morphology more complicated.

Marathi Morphology solutions to the challenges Morphological analysis is done category wise. Parameters for changes in the root word are identified. Rules are constructed in the tabular form to facilitate computation.

Marathi Word Classes Nouns Pronouns Adjectives Verbs Adverbs Postpositions Conjunctions Interjections Particles Punctuation Mark

Postpositions Postposition is the morpheme that follows the words and shows the relation between the word that is followed and other word in the sentences. Case markers and shabdayogi avyaya are classified as postpositions in Marathi because they show same behavior. (ref. ‘Classification of Words’, Veena Dixit, proceedings of 26 th AICL, Shilong, 2004 )

Postpositions (continued) In Marathi, postpositions are attached to all classes of words except interjection. examplesexamples When a postposition is attached to a stem it produces mainly adverb, but also, adjective and conjunction. Postpositions are handled along with other word classes. 5 subgroups of postpositions are identified on the basis of what is the possible order of their attachment and to which group of words they can be attached.

Particles Strings like ही – hi_also, च – cha_only, सुद्धा – suddha_also, are –sometimes attached to other words (e.g.. खाली – khaali _under – खालीसुद्धा - khaalisuddhaa_under also / झाड - jhaaDa _ tree - झाडसुद्धा - jhaaDasuddhaa _ tree also ) –or sometimes they are written separately (e.g.. झाडाखाली - jhaaDaakhaali_ under the tree – झाडाखाली सुद्धा - jhaaDaakhaalisuddhaa_ under the tree also). When such words are attached to other words, the word to which it is attached, does not get inflected.

Interjections Interjections are identified from the lexicon and stored to produce the tag. Conjunctions Conjunctions are identified from the lexicon and stored to produce the tag. Morphology also plays a role in the case of conjunctions.

Conjunctions (continued) When some of Marathi postpositions are attached to a pair of demonstrative pronouns, they produce a pair of conjunctions in some instances. जो – ज्यापासून (jo – jyaapaasuna --- which – from which) तो – त्यापासून (to – tyaapaasuna --- that – from that) ज्यापासून काल सुरुवात केली, त्यापासून आज नक्कीच सुरुवात करायला नको. – jyaapaasuna kaala suruvaata keli, tyaapaasun aaja nakkicha suruvaata karaayalaa nako_One should not start from the (same point) from which it was started yesterday.

Pronouns Number of inflected forms of a pronoun and the rules describing such inflection are almost equal in number. Number of pronouns and their respective inflected forms are finite and less when compared to verbs and nouns. All inflected forms of the pronouns will be stored to produce the tag for pronoun. Derivational morphology of pronoun is handled with rules.

Pronouns (continued) Inflectional forms of pronouns act either as adjectives ( माझा – maajhaa_my) or as adverbs ( मला – malaa_to me ) or as conjunctions ( जो – ज्यापासून (jo – jyaapaasuna --- which – from which) तो – त्यापासून (to – tyaapaasuna --- that – from that)).

Pronouns (continued) All together 29 pronouns have 526 inflectional forms, which are either words or stems. 21 paradigms are identified generating several rules.

Adjectives Adjectives are mainly, inflectional and non - inflectional. Adjectives inflect for gender, number and attachment of postposition to the noun they modify. Adjectives in Marathi agree in gender and number with the nouns they modify.

Adjectives (continued) All inflectional adjectives belong to one paradigm, which corresponds to several rules for generating inflectional and derivational forms from an adjective. Most of ‘aa’ ending adjectives agree with masculine nouns and further get inflected according to the gender and number of the noun they modify. ( मोकळा / मोकळी / मोकळे / मोकळ्या _mokaLaa / mokaLi / mokaLe / mokaLyaa_empty) There are some exceptions to this rule, such as, ( जादा - jaada_extra, नाना – naanaa_different, वाया vaayaa_wasted).

Adverbs Adverbs are mainly, inflectional and non - inflectional. Adverbs inflect for attachment of postpositions. खाली – ( khaali_under –-- खालपासून – khaalapaasuna _from the underneath )

Verbs and Nouns will be discussed in next sessions. Thank you. Veena Dixit 11/ 10 /2005