A Computational Analysis of Nepali Morphology: A Model for Natural Language Processing

Abstract

The main goal of this study is to present a computational analysis of morphology in Nepali for developing a model for natural language processing by applying the finite state approach. The morphological categories have been analyzed according to the principle of Two-level morphology (Koskeniemmi 1983), and these categories have been implemented using Xerox finite state tool (Beesley and Kartumnen 2003) to create the morphological analyzer. A version of finite state automaton called finite state transducer is used in this study which handles relation between two languages, namely upper language and lower language. Upper language is equivalent to lexical level and lower language is equivalent to surface level. The finite state transducer is bidirectional, i.e., moving from surface level to lexical level is analysis and from lexical level to surface level is generation. This study is organized into eight chapters. Chapter 1 presents the general morphological concepts, the objectives, methodology, the significance and limitations of the study. Chapter 2 presents the theoretical framework that is adopted for the study. Chapter 3 analyzes nouns, pronouns, adjectives, numerals and classifiers in Nepali. Chapter 4 analyzes the verbs in Nepali from computational approach in the first part and verbal inflections in the second part. Chapter 5 deals with indeclinable words in Nepali. Chapter 6 analyzes the derivational process. Chapter 7 implements the outcome of analysis in previous chapters into a finite state transducer using Xerox Finite State Tool. Chapter 8 summarizes the findings of the study. This study has identified fourteen groups of nouns, eight groups of pronouns, four groups of adjectives, one group of cardinal numerals, two groups of ordinal numerals, three groups of classifiers, ten groups of verbs, seven groups of adverbs, two groups of conjunctions, three groups of postpositions, one group of particles and fifteen groups of derivations in Nepali. The phonological rules for each group have also been identified. The finite state transducer for each group with corresponding morphological tags and phonological rules have been created; and all of them have been put together into a single transducer which can be used as a morphological analyzer for Nepali.