A prototype dependency treebank for B reton (2018)

Abstract: This paper describes the development of the first syntactically-annotated corpus of Breton. The corpus is part of the Universal Dependencies project. In the paper we describe how the corpus was prepared, some Breton-specific constructions that required special treatment, and in addition we give results for parsing Breton using a number of off-the-shelf data-driven parsers.

## introduction treebanks, or collections of sentences annotated according to some schema, have existed for decades, under a variety of standards intended to represent various details. the universal dependencies project @xcite is a multilingual collection of treebanks annotated with dependency relations; at the time of writing of this paper, it consists of 115 treebanks in 65 languages. the project aims to enable a cross-linguistically valid schema of dependency annotation, and heavily depends on public contribution of mostly open resources. the existence of this unified collection of treebanks has led to extremely simplified parser creation and evaluation, as exemplified in the conll 2017 shared task on dependency parsing @xcite . this paper describes a treebank for breton, a language spoken in brittany in the north-west of france. the treebank will be included in the conll 2018 shared task on dependency parsing², and we expect that it would provide a starting point for further annotation of breton. the treebank is the second celtic language treebank, and the first treebank for a language of the brythonic subgroup of celtic, in ¹b : deskrivañ a ra ar pennad-mañ savidigezh ar c'horpus kentañ bet notennet e ereadurezh e brezhoneg. ul lodenn eus ar raktres «universal dependencies» eo ar c'horpus-se. en teuliad e teskrivomp penaos e oa bet prientet ar c'horpus ha penaos e oa bet pledet gant frammoù dibar zo eus ar brezhoneg. ouzhpenn-se, reiñ a reomp disoc'hoù dezrannadur ereadurel ar brezhoneg gant dezrannerioù ereadurel zo. the paper is laid out as follows, in section 2 we give a brief sociolinguistic and typological overview of the breton. then in section 3 we describe some prior work on computational resources and tools for breton. in section 4 we describe the composition of the corpus, and in section 5 we describe some details of the annotation guidelines, paying attention to breton-specific phenomena. section 6.1 reports on a small experiment with three popular data-driven parsers, and is followed by some avenues for future work in section 7 and conclusions in section 8. ## breton breton (in breton brezhoneg) is a celtic language of the brythonic branch which is today largely spoken in brittany in the north-west of france. historically it was spoken to different degrees throughout brittany, but has been losing territory to french since the 12th century, most rapidly in the last 100 years. the language is classed as a language in "serious danger of extinction" by the unesco red book on endangered languages @xcite . for an overview of breton grammar, see @xcite and for full grammars see @xcite and @xcite . the language has two grammatical genders (masculine and feminine), two numbers (singular and plural)³ and like the other brythonic languages has lost the case system. like other celtic languages, breton has contractions of pronouns and prepositions,⁴ for example ganin 'with me' and ganit 'with you' (from gant 'with'). unlike other celtic languages, breton also has an indefinite article un 'a', and an analytic passive construction with the verb bezañ 'be'.⁵ breton also exhibits the initial consonant mutation typical to celtic languages, and has a fusional morphological system. syntactically, breton has flexible constituent order within the sentence; vso, svo and ovs are frequently used with vso -the classic celtic order -being the most prominent. adjectives follow nouns while other modifiers (adjectives, determiners) precede them. verbs inflect for person, number, tense and mood. auxiliaries may follow or precede the main verb. ## related work there has been very little work to date on natural language processing for breton. among the related articles we may find tyers ( 2009 ) who use a morphological analyser and bilingual dictionary to generate training data for statistical machine translation, and tyers (2010) who describe a free/open-source rulebased machine translation system for breton to french. there has been more recent work by poibeau (2014) on treating initial consonant mutations with finite-state transducers. there are a number of written grammars of breton, we have particularly relied on @xcite and @xcite . whilst no breton treebanks exist that we know of, there are two existing treebanks for one celtic language, viz. irish @xcite . ## corpus the corpus is composed of texts from a variety of domains (see