Learning chemistry in a new language
Beside the resources for learning chemistry Poutnik indicated, you may learn some of the chemical names and concepts from wikipedia, too. Frequently, articles are available in more than one language and sometimes a version in an other language offers additional details, too.  You find the switch at the left side of the pages:



Typically, you find some references at the bottom of these pages which may be accessible by you without going to a university library.

As side note: You mention that you did not yet start to study chemistry at a university at all.  Hence, it is too early for you to judge if a Slovak (or Czech, given the language) university is good or bad for your aspiration of a PhD in chemistry; because you likely do not know yet which specialty will attract your interest, nor potential co-workers and supervisors.  Remain active to obtain a solid chemical education first -- a chemistry department with classes about 30--60 students per year may be more helpful for laying such a foundation, than a larger institution where you become "just a number".  Do not exclude smaller departments (and countries) just because they are smaller, or less frequently in the scientific media, than others when thinking about a move to an other institution is an opportunity.