We analyze the language-internal variation in the class of dative predicatives in Bulgarian and Russian. For each language, a test questionnaire is prepared. The stimuli are grouped into 15 thematic classes for Russian and 19 thematic classes for Bulgarian and tested on native speakers. Their responses provide a sample of stimuli ranked according to the approval rate. The same set of stimuli is tested on Russian National Corpus and Bulgarian National Corpus, which provided the second ranked sample. The volume and structure of the class of dative predicatives is established by the ratio of these ranked samples.