Derivational Relations in Czech WordNet

In the paper we describe enriching Czech WordNet with the derivational relations that in highly inflectional languages like Czech form typical derivational nests (or subnets). Derivational relations are mostly of semantic nature and their regularity in Czech allows us to add them to the WordNet almost automatically. For this purpose we have used the derivational version of morphological analyzer Ajka that is able to handle the basic and most productive derivational relations in Czech. Using a special derivational interface developed in our NLP Lab we have explored the semantic nature of the selected noun derivational suffixes and established a set of the semantically labeled derivational relations – presently 14. We have added them to the Czech WordNet and in this way enriched it with approx. 30 000 new Czech synsets. A similar enrichment for Princeton WordNet has been reported in its recently released version 3.0, we will comment on the partial similarities and differences.