Creating Reverse Bilingual Dictionaries

Proceedings of NAACL-HLT 2013, pages 524–528, Atlanta, Georgia, 9–14 June 2013. c⃝2013 Association for Computational Linguistics Creating Reverse Bilingual Dictionaries Khang Nhut Lam Department of Computer Science University of Colorado Colorado Springs, USA klam2@uccs.edu Jugal Kalita Department of Computer Science University of Colorado Colorado Springs, USA jkalita@uccs.edu Abstract Bilingual dictionaries are expensive resources and not many are available when one of the languages is resource-poor. In this paper, we propose algorithms for creation of new reverse bilingual dictionaries from existing bilingual dictionaries in which English is one of the two languages. Our algorithms exploit the simi- larity between word-concept pairs using the English Wordnet to produce reverse dictionary entries. Since our algorithms rely on available bilingual dictionaries, they are applicable to any bilingual dictionary as long as one of the two languages has Wordnet type lexical ontol- ogy. 1 Introduction The Ethnologue organization1 lists 6,809 distinct languages in the world, most of which are resource- poor. Most existing online bilingual dictionaries are between two resource-rich languages (e.g., English, Spanish, French or German) or between a resource- rich language and a resource-poor language. There are languages for which we are lucky to find a single bilingual dictionary online. For example, the Uni- versity of Chicago hosts bilingual dictionaries from 29 Southeast Asian languages2, but many of these languages have only one bilingual dictionary online. Existing algorithms for creating new bilingual dictionaries use intermediate languages or interme- diate dictionaries to find chains of words with the same meaning. For example, (Gollins and Sander- son, 2001) use lexical triangulation to translate in parallel across multiple intermediate languages and 1http://www.ethnologue.com/ 2http://dsal.uchicago.edu/dictionaries/list.html fuse the results. They query several existing dictio- naries and then merge results to maximize accuracy. They use four pivot languages, German, Spanish, Dutch and Italian, as intermediate languages. An- other existing approach for creating bilingual dictio- naries is using probabilistic inference (Mausam et al., 2010). They organize dictionaries in a graph topology and use random walks and probabilistic graph sampling. (Shaw et al., 2011) propose a set of algorithms to create a reverse dictionary in the context of single language by using converse map- ping. In particular, given an English-English dictio- nary, they attempt to find the original words or terms given a synonymous word or phrase describing the meaning of a word. The goal of this research is to study the feasibility of creating a reverse dictionary by using only one ex- isting dictionary and Wordnet lexical ontology. For example, given a Karbi3-English dictionary, we will construct an ENG-AJZ dictionary. The remainder of this paper is organized as follows. In Section 2, we discuss the nature of bilingual dictionaries. Section 3 describes the algorithms we propose to create new bilingual dictionaries from existing dictionaries. Re- sults of our experiments are presented in Section 4. Section 5 concludes the paper. 2 Existing Online Bilingual Dictionaries Powerful online translators developed by Google and Bing provide pairwise translations (including for individual words) for 65 and 40 languages, re- spectively. Wiktionary, a dictionary created by …

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