Abstract
In the present paper, we deal with diatheses in Czech from a lexicographic point of view. We propose a method of their description in the valency lexicon of Czech verbs VALLEX.
We distinguish grammatical and semantic diatheses as two typologically different changes in verbal valency structure. In case of grammatical diatheses, these changes are regular enough to be described by formal syntactic rules.
In contrast, the changes in valency structure of verbs associated with semantic diatheses vary even within one type of diathesis. Thus for the latter type, we propose to set separate valency frames corresponding to their members and to capture the changes in verbal valency structure by lexical rules based on an adequate lexical-semantic representation of verb meaning.