... achieving accuracy of 97.98%, which is a significant improve-ment over the state -of- the-art for Bulgarian.1 IntroductionPart -of- speech (POS) tagging is the task of as-signing each of the words in ... four major types of ambiguity:1. Between the wordforms of the same lexeme,i.e., in the paradigm. For example, ,an inflected form of (‘sofa’, mascu-line), can mean (a) ‘the sofa’ (definite, singu-lar, ... person, number,definiteness, etc.493Proceedings of the 13th Conference of the European Chapter of the Association for Computational Linguistics, pages 4 92–50 2,Avignon, France, April 23 - 27 2012.c2012...