CASSAurus: A Resource of Simpler Spanish Synonyms

CASSAurus: A Resource of Simpler Spanish Synonyms Ricardo Baeza-Yates,1 Luz Rello,1∗ Julia Dembowski2 Web Research Group, DTIC1 Computational Linguistics Dept.2 Universitat Pompeu Fabra1 Saarland University2 Barcelona, Spain1 Saarland, Germany2 {rbaeza,luzrello}@acm.org juliad@coli.uni-saarland.de Abstract In this work we introduce and describe a language resource composed of lists of simpler synonyms for Spanish. The synonyms are divided in different senses taken from the Spanish OpenThesaurus, where context disambiguation was performed by using statistical information from the Web and Google Books Ngrams. This resource is freely available online and can be used for different NLP tasks such as lexical simplification. Indeed, so far it has been already integrated into four tools. Keywords: Lexical simplification, synonyms, Spanish OpenThesaurus, Google Books Ngrams, Spanish. 1. Introduction There are few online free resources regarding synonyms in most languages. That is certainly the case in Spanish, where the OpenThesaurus is the main free resource. How- ever, OpenThesaurus does not have information of what synonyms are simpler or more complex, something crucial to perform lexical simplification. CASSAurus is, to the best of our knowledge, the first freely available resource that ranks synonyms depending on their complexity. The resource consists of over 40 thousand complex words with their corresponding synonyms depending on the sense of the word. The resource is freely available online.1 The rest of the paper is organized as follows. Related work is covered in Section 2.. In Section 3. we summarize the al- gorithm used to generate the simpler synonyms while Sec- tion 4. details the resource. In Section 5. we give an ex- ample of the use of the resource and its evaluation. We end with some concluding remarks and future work in Sec- tion 6.. 2. Related Work One of the main limitations that previous lexical simplifi- cation studies in Spanish point out is the lack of resources in this language. For instance, there is no Simple Wikipedia in Spanish, while there is a Simple English Wikipedia (Coster and Kauchak, 2011) that has lead to new approaches for lexi- cal simplification in English (Yatskar et al., 2010; Biran et al., 2011). As far as we know, the existing resources previously used for lexical simplification in Spanish are the following. Simplext Corpus (Bott and Saggion, 2012) is used in the first lexical simplification system for Spanish (Bott et al., 2012). Simplext Corpus is a set of 200 news articles of which 40 have been manually simplified. The parallel part of this corpus contains 6,595 words of original and 3,912 words of simplified text. All texts have been annotated us- ∗ Currently at HCI Institute, Carnegie Mellon University, Pittsburgh, USA. 1grupoweb.upf.es/WRG/ & www.luzrello.com ing Freeling, including part-of-speech tagging, named en- tity recognition and parsing (Padr´o et al., 2010). Another language resource used for Spanish lexical simpli- fication (Bott and Saggion, 2012) is the Spanish OpenThe- saurus (SpOT).2 SpOT is freely available under the GNU Lesser General Public License, to be used with OpenOf- fice.org. This thesaurus provides 21,378 target words (lem- mas) and a total of 44,348 different …

Content truncated to 500 words