ICLSL 2017
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/18326
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Item A Corpus-Based Morphological Analysis of Sinhala Verbs.(The Third International Conference on Linguistics in Sri Lanka, ICLSL 2017. Department of Linguistics, University of Kelaniya, Sri Lanka., 2017) Dilshani, W.S.N.; Dias, G.Verbs are essential components of a meaningful sentence and are important in understanding the sentence structure. This paper presents a morphological analysis of Sinhala verbs by combining traditional Sinhala grammar with an analysis of current usage based on a corpus of official documents. Sinhala verbs may be classified into a number of groups based on their morphology. However, there is currently no well-defined methodology to classify a particular verb. It is hypothesized that verb morphology patterns may be identified by analysis of a Sinhala text corpus. On the basis of that hypothesis, this research proposes a classification for Sinhala verbs based on their morphology which allows the morphological analysis of verbs in Sinhala text, and also the derivation of morphological rules for each class of verbs. This classification and rules are derived from an analysis of the corpus of official documents. Additionally, the rules were tested by applying them to another part of the corpus. This also allows the identification of irregular verbs, which do not fall into standard classes. With the analysis, it was identified that the usage of tenses in contemporary official documents is more complex than those given in grammar texts and different combinations of Sinhala grammatical forms are used to denote the time periods among standard tenses. Moreover, other writing forms of Sinhala were identified and it is shown that the existing classification of verbs in traditional grammar is insufficient to handle modern usage of the language.Item A Comprehensive Part of Speech (POS) Tag Set for Sinhala Language.(The Third International Conference on Linguistics in Sri Lanka, ICLSL 2017. Department of Linguistics, University of Kelaniya, Sri Lanka., 2017) Dilshani, N.; Fernando, S.; Ranathunga, S.; Jayasena, S.; Dias, G.Sinhala, which belongs to Indo-Aryan language family, is a morphologically complex language. Most of the features of the words are postpositionally affixed to the root word. Thus, well-developed Part of Speech (POS) tag sets for languages such as English cannot be easily adopted to create a POS tag set for Sinhala. Moreover, currently available Sinhala POS tag sets have many limitations such as the unavailability of tags for certain words. The objective of the research is to overcome and to identify ambiguities and limitations of the present POS tag sets for Sinhala language, and to develop a comprehensive multi-level tag set for Sinhala language. The new tag set was designed after a thorough evaluation of different types of corpora such as news articles and official government letters, and as well as an analysis of the existing POS tag set for Sinhala. This new tag set consists of 148 tags and is organized into 3 levels. Thus, it covers most of the word classes and inflection based grammatical variations of the Sinhala language. The ultimate purpose of developing this tag set is to implement an automatic POS tagger, which is an essential tool in implementing Natural Language Processing Applications. To train the automatic POS tagger, a corpus of 300000 words has been POS annotated manually using this tag set. This tag set produced an overall accuracy of 84.68% and it bypasses the other Sinhala POS taggers. However, this annotation is done only up to level 2 in the tag set. Annotating at level 3 has the potential to introduce many ambiguities to the manual annotation process, due to the large number of POS tags. Thus this opens up new research avenues to investigate on the use of inflectional morphological features of Sinhala language, in order to determine the POS tag of a word at the third level.