[Jubal]

Ok, ready for the ULTIMATE geek answer?

You see, the names you hear are a TRANSLATION of a galactic language of a spoken name mentioned in a star far, far, away. So translated you hear "Luke" because that is the equivalent to what that name would be in the Terran culture. But the name does not sound like "Luke" in that other language but that language' equivalent of the name.

Names that sound alien or bizarre are actually closer to how they sound in that non-Terran language because there is no Terran equivalent when translated, so the original sound is used.