Unsupervised POS tagging has been traditionally approached with relative success (Merialdo, 1994;Kupiec, 1992) by HMM-based generative models, employing EM parameters estimation using the Baum-Welch algorithm.
, in order to support the wider tagset used by the KC analyzer: (1) The SW set for adjectives, copulas, existentials, personal pronouns, verbs and participles, is composed of all gender-number inflections; (2) The SW set for common nouns is composed of all number inflections, with definite article variation for absolute noun; (3) Prefix variations for proper nouns; (4) Gender variation for numerals; and (5) Gendernumber variation for all suffixes (possessive, nominative and accusative).