U niversal D ependencies for A lbanian (2020)

Abstract: In this paper, we introduce the first Universal Dependencies (UD) treebank for standard Albanian, consisting of 60 sentences collected from the Albanian Wikipedia, annotated with lemmas, universal part-of-speech tags, morphological features and syntactic dependencies. In addition to presenting the treebank itself, we discuss a selection of linguistic constructions in Albanian whose analysis in UD is not self-evident, including core arguments and the status of indirect objects, pronominal clitics, genitive constructions, prearticulated adjectives, and modal verbs.

## introduction albanian is an indo-european language and also part of the balkan sprachbund. @xcite it is spoken primarily in albania and secondarily in neighbouring balkan countries by albanian minorities but also elsewhere in europe and outside by the albanian diaspora. its vocabulary, but even more so its grammar, exhibits a lot of similarities and parallelisms with the languages of the balkan sprachbund, while it also features linguistic constructions that could be characterized as idiosyncratic. computational and other online resources that could facilitate nlp research and comparative studies of albanian are scarce. a large part-of-speech tagged corpus for the language was created only recently by kote et al. (2019), but there is still no corresponding treebank with full syntactic annotation, which means that it is hard to develop language technology applications that require both tagging and parsing. it is in this context that we have developed the first universal dependencies (ud) treebank for albanian, called ud albanian-tsa. @xcite although still very limited in size, it constitutes a first step towards developing a large-scale treebank within the ud scheme, enabling nlp research as well as comparative studies involving other languages, and there is also research showing that even a few annotated sentences can contribute to good parsing results (meechan-maddon and nivre, 2019). in the following sections we introduce some of the key features of the albanian language (section 2), provide a brief summary of related work with regard to nlp for albanian (section 3), and describe the steps taken to develop the treebank (section 4). we then discuss in some detail a selection of linguistic constructions in albanian that pose challenges for the ud annotation framework and that are interesting from a cross-linguistic perspective (section 5). ## the albanian language albanian belongs to the indo-european family of languages, but it constitutes its own branch within the family. it is spoken by around 7.5 million people, of which, due to the albanian diaspora, less than 3 million are estimated to reside in albania (hoxha and baxhaku, 2019). there are two main albanian dialects, the tosk and the gheg, with the former being the one standard albanian is based on. its alphabet relies on the latin one and comprises 36 letters, 9 of which are digraphs (dh, gj, ll, nj, this work is licensed under a creative commons attribution 4.0 international license. license details: http:// creativecommons.org/licenses/by/4.0/ . ## nlp for albanian in recent years, the development of nlp resources for albanian has been increasing. most research has focused on the morphological analysis and the creation of part-of-speech tagging models. trommer and kallulli (2004) first introduced a morphological analyzer that made use of off-line components, while later on piton and lagji (2008), performing a morphological study of albanian, developed electronic dictionaries of inflected forms as well as transducers using nooj. in the area of part-of-speech tagging, kabashi and proisl (2018) proposed a part-of-speech tagset after noticing there did not exist one of moderate size, mapping it also to the ud tagset (nivre et al., 2016; nivre et al., 2020). they built on their own previous work (kabashi and proisl, 2016) and that of other researchers, such as that of hasanaj (2009), who had developed a statistical part-of-speech tagging model with accuracy around 70%, and kadriu (2013) who had presented a part-of-speech tagging model using the nltk toolkit. in 2019, the authors foot_1 of the albanian national corpus foot_2 (morozova and rusakov, 2014) (anc) developed and made publicly available in the official website of the anc a lemmatizer, tagger and morphological analyzer for albanian. however, they use their own part-of-speech tagset and do not rely on the ud annotation scheme, and there is no disambiguation of either lemmatization, tagging or morphological analysis. anc itself contains around 20 million tokens and is therefore the largest resource currently available for albanian. also recently, kote et al. (2019) presented an albanian corpus with part-of-speech tags and morphological features containing around 118,000 tokens. additionally, the team trained a neural morphological tagger and lemmatizer which achieved promising results, the best of which being 92.74% in part-ofspeech tagging. the annotation of the corpus was based on the ud guidelines and underwent a manual review. ## treebank development in this section, we describe the development of ud albanian-tsa. given the lack of preprocessing tools and resources for albanian compatible with the ud framework, foot_3 most tasks undertaken in the creation of the treebank were performed manually. however, some steps, such as word segmentation, lemmatization, tagging and morphological analysis were semi-automated through scripts that we developed or tools that were available from other researchers, as described in more detail below. in the end, the entire treebank underwent manual checking and correction, so as to resolve cases of ambiguity, eliminate errors and ensure overall consistency, and was also tested with the ud validation script. ## conclusion albanian is a morphologically rich language with several grammatical particularities which can prove challenging when trying to find analogies to other languages. in this paper, we presented the first ud treebank for standard albanian, which features some of the most characteristic constructions of albanian. we gave an overview of the formal aspects of the language and analyzed in more detail a few dependency structures that are rather rare or even unique in ud and call for special solutions. although its current size is not sufficient for the training of tools such as parsers, which in turn could be used for the development of more sophisticated nlp applications, we envision that this starter treebank will encourage further work in the area and will be enlarged in the future.