Universal Dependencies for Amharic

Universal Dependencies for Amharic Binyam Ephrem Seyoum1, Yusuke Miyao2, Baye Yimam Mekonnen3 Addis Ababa University1,3, National Institute of Informatics2 P.O.Box 1176, Addis Ababa1,3, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-84302 binyam.ephrem@aau.edu.et1, yusuke@nii.ac.jp2, baye.yimam@aau.edu.et3 Abstract In this paper, we describe the process of creating an Amharic Dependency Treebank, which is the first attempt to introduce Universal Dependencies (UD) into Amharic. Amharic is a morphologically-rich and less-resourced language within the Semitic language family. In Amharic, an orthographic word may be bundled with information other than morphology. There are some clitics attached to major lexical categories with grammatical functions. We first explain the segmentation of clitics, which is problematic to retrieve from the orthographic word due to morpheme co-occurrence restriction, assimilation and ambiguity of the clitics. Then, we describe the annotation processes for POS tagging, morphological information and dependency relations. Based on this, we have created a Treebank of 1,096 sentences. Keywords: Treebank, Universal Dependencies, Amharic 1. Introduction In recent years, different language processing applications demand state-of-the-art parsers. Question answering, ma- chine translation, information summarization and similar applications require high-quality parsers. In order to train or develop an efficient parser, it has become an estab- lished practice to create a Treebank, linguistically anno- tated corpus which includes, in most cases, morphological and syntactic annotations. Treebanks play an important role to the research in parsing natural languages. They can also be used in testing linguistic theories and scrutinize corpus-based language analysis. Furthermore, treebanks are essential resources for building and testing data-driven tools such as POS taggers and morphological analyzers where they serve as a gold standard for these tools. Treebanks have been developed for well-resourced lan- guages in different frameworks such as Phrase Structure, HPSG, and Dependency. However, there are no treebanks for Amharic in any form. In this study, an attempt will be done to create treebanks for Amharic. Apart from develop- ing this resource, the research contributes to the general problem of parsing Morphologically-rich Languages (MRL). In such languages, a dependency relation exists not only between the orthographic words (space-delimited tokens) but also relations within a word itself (Goldberg, Elhadad, and Gurion, 2009). Because of this, clitics at- tached to orthographic words need to be segmented for proper syntactic analysis. However, automatic segmenta- tion of the prefix and the suffix clitics from the ortho- graphic word in Amharic is problematic due to morpheme co-occurrence restriction, assimilation and ambiguity of the clitics (cf. Section 3 and 4). In this paper, first we dis- cuss clitic segmentation then we describe the creation of the treebanks which are annotated for POS tag, morpho- logical information and dependency relation. 2. Background Universal Dependencies (UD) project is a collaborative effort to ensure consistent annotations across many lan- guages. This project has benefited from earlier efforts in- cluding universal annotation of Google Universal part-of- speech tags (Petrov, Das, and Mcdonald, 2012), mor- phosyntactic features (Zeman, 2008; Zeman et al., 2012) and Stanford Dependencies (de Marneffe et al., 2014; de Marneffe and Manning, 2008). The objective of UD, as stated in …

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