I did the same thing with the Narnia books when I was a kid. I thought it was "Alsan" for literally years, and even once I got straightened out, it took forever before "Aslan" seemed right.
I clicked on an interesting link over in
lmbujold that goes over official pronunciations per LMB. I was surprised by the pronunciation given for the family including Aral's first wife, Ges, Byerly, Dono, and Richars. How in the world could it be pronounced vor-ROOT-yr? I'd always figured it for vor-ROOY-tr, or perhaps closer to vor-ROY-tr.
Oh. It's not spelled Vorruyter. It's Vorrutyer. ::headdesk:: That's annoying. And embarassing.
ETA that link and another useful one:
Pronunciation guide:
http://www.dendarii.com/dictionary.html Nexus Map:
http://pw1.netcom.com/~fresne/nexus.htm