I'm reading the 3rd Malazan book at the moment. At least I was, until my library loan was due and somebody else borrowed it. I was stuck with the English version (I mainly read in German) and had to learn all the character names anew. Some are easy to translate (Silverfox is Silberfuchs), however Whiskeyjack gave me a hard time (He's called Elster in German).
But now I got my beloved German version back, so I guess my brain has to adapt again.
Yeah, that is one of the more prevalent problems with bookwyrm if you ask me. I mainly read in German, so I do the same. This is less an issue with English books, but I think it really depends on how popular they are in general and on bookwyrm. It helps, however, if you choose a boowyrm instance with many French people. If my current read is a German translation of an English original, then another possibility I consider is to select the English original, if adding the book manually is too much a hassle.