The present paper describes a semi-automatic method of adding derivational links to the lexical database DeriNet by identifying verbs which are derived by suffixation and constitute aspectual pairs. It briefly introduces the notion of aspect in Czech and discusses the account of aspect in the Czech linguistic literature and in existing data resources.
As its main focus, it presents an approach to identifying aspectual pairs based on extraction of such pairs from the VALLEX valency dictionary, identification of suffix substitution rules and subsequent manual annotation, which resulted in the addition of almost 6,000 derivational links into the DeriNet database.