slovanských
Slovanských is the genitive plural form of the Czech adjective slovanský, meaning Slavic. It is used to indicate relation to Slavic peoples or languages and to modify nouns in contexts that require genitive, for example in phrases such as rod slovanských jazyků (the family of Slavic languages) or tradice slovanských národů (traditions of the Slavic peoples).
The base form slovanský yields other gender and number forms in Czech: slovanský (masculine singular), slovanská
Etymologically, slovanský derives from the Slavic root related to Slavs, with cognates found in many languages
In summary, slovanských functions as a grammatical form rather than a standalone noun, serving to qualify nouns