Automatic Construction of Tamil UNL Dictionary

Abstract

In this paper, we propose an automatic tool for creating dictionary entries of Tamil words for the Universal Networking Language (UNL). Dictionary plays a crucial role in many NLP applications especially in machine translation (MT) systems. However, creating dictionary entries manually is a time consuming process. Moreover the UNL dictionary consists of additional features such as semantic constraints and attributes. To address this complex task, we propose a domain specific approach where the dictionary entries are created automatically using other word-based resources such as WordNet, bilingual dictionaries, and the UNL ontology. For the source of domain specific words, we use domain specific documents from the web. The resources used for extracting meaningful words from the documents are: Morphological analyzer, to extract the grammatical information of a given word, WordNet, to identify the semantics of the given word and UNL KB (Knowledge Base) to obtain the semantic constraints of a given word. Semantic constraints help to know the tense mood and aspect of the given word. Sometimes these semantic constraints may not be determined correctly by the automatic process. In such cases, a semantic similarity based filtering method based on UNL ontology is used to remove the incorrect dictionary entries. Thus, this automatic dictionary tool handles words semantically and also improves the correctness of the dictionary.