It seems like it is based on a combination of an earlier draft of the novel and the translator’s own ideas, because it contains things that were in Stoker’s notes but not in the final manuscript, and a lot of Scandinavian mythology is added. It is more overtly erotic and political as well.
It has been translated into English (this translation is dated 2017)
However, far be it from me too discourage anyone from learning a language. After all, what better exemplifies the fallibility of translation than this story?