Finite-State Morphology of Estonian: Two-Levelness Extended

The paper is concentrated on modeling the Estonian morphology in the framework of twolevel morphology model. The result is a consistent description of Estonian morphology, which consists of a network of lexicons (root lexicons cover 2500 most frequent word roots) and two-level rules. The main rule set contains 45 rules, which describe various stem changes. The subset of rules dealing with stem internal changes is applied separately as well. For modeling the derivation process a new solution has been found – to extend the two-levelness into the upper side of the morphological transducer (to the lemmas). It has been shown that finitestate methods are applicable and sufficient for describing Estonian inflectional processes, but word formation rules, especially compounding, require more investigation.