The "pop-up function" is language-agnostic, and relies on the metadata of both the book and the dictionary being correct. In other words: the books' language metadata must be correctly set to "russian", and the dictionary's input language must be set to russian too.
I believe that you can use the metadata editor
to verify (and possibly change) the metadata, but I'm not an expert on that. Just try it out.
PS: Please update your profile to include your device. This makes it much easier for everyone to see what "constellation" you are talking about.