The Geometry of Language – a Space Semantic Network of Bulgarian Nominal Inflectional Morphology VELISLAVA STOYKOVA Bulgarian Academy of Sciences Institute for Bulgarian Language 52, Shipchensky proh. str. bl. 17, 1113 Sofia BULGARIA vili1@bas.bg CHAVDAR LOZANOV University of Sofia Department of Geometry 5, J. Bourchier blvd., 1164 Sofia BULGARIA lozanov@fmi.uni-sofia.bg Abstract: In this * work we present a computationally tractable model of Bulgarian nominal inflectional morphology for the feature of definiteness using orthogonal semantic networks. We use DATR language for lexical knowledge presentation for the implementation and we define the basic principles of the encoding in terms of its linguistic motivation, namely, the semantics and the grammar features of definiteness in Bulgarian language. Further, we explain a fragment of semantic network encoding of nouns and evaluate different inflected forms. Finally, we offer a geometrical interpretation of the encoded semantic network in the space by visual representation of orthogonal semantic relationship. Key–Words: Grammar knowledge presentation, semantic networks, computational morphology, DATR language for lexical knowledge presentation, semantic networks visualisation. 1 Introduction The standard Bulgarian language belongs to the group of Slavonic languages but it does not use cases for syn- tactic representation. At the same time, it has very rich inflectional system – both for derivational and for inflectional morphology [5], and it uses prepositions and a base word form instead case declinations to ex- press syntactic relationships. The second important grammar feature of Bulgar- ian, in which it differs with all Slavonic languages, is the feature of definite article. The definite article in Bulgarian is an ending morpheme [5, 7], which gives a priority to morphological interpretations in- stead syntactic ones. Concerning its syntax, Bulgarian language uses relatively free word order since the subject can take every syntactic position in the sentence (including the last one) and the definite article is the only marker of it. At the level of syntax, the definite article shows the subject (when it is not a proper name) since Bulgarian language uses a relatively free word order, so giving a detailed formal morphological interpretation of the definite article will significantly improve the task of part-of-speech parsing. * Partially supported by Grant No 192/2010 of Science Fund of Sofia University ”St. Kliment Ohridsky”. 2 The semantics of definiteness and its formal morphological marker According to traditional academic descriptive gram- mar works [5], the semantics of definiteness in stan- dard Bulgarian language is expressed in three ways: lexical, morphological, and syntactic. The lexical way of expressing definiteness is closely related to the lexical semantics of a particu- lar lexeme, and it would not be of semantic value for the formal interpretation mainly because most of the formal grammar interpretations are supposed to deal with one-sense lexeme, which is the simplest possible type of lexeme. At the syntactic level, the definiteness in Bulgar- ian may express various types of semantic relation- ships like a case (to show subject), part-of-whole, deixis etc. The definite article can assign an individ- ual, or quantity definiteness, and it has a generic use as well. Some authors tend to define the semantics of this feature at a hypertext level in pragmatic perspec- tive of the topic/focus relationships. Instead very many existing descriptive grammar works devoted to the problem, the semantics of defi- niteness in Bulgarian seems still not a sufficiently well studied phenomenon. The syntactic function of defi- niteness in Bulgarian is expressed by a formal mor- LATEST TRENDS on COMPUTERS (Volume II) ISSN: 1792-4251 721 ISBN: 978-960-474-213-4