Why the different spellings?

I've had this question on my mind for a long time. My family, at least as far back as my grandfather, spells it Numerick. I've known since I was a kid that my dad's half-brother Richard had changed the spelling of his name to Numerich. Several years ago my Uncle Derryl explained that Richard believed that he had changed it to the original spelling. I'm not sure Uncle Richard was correct, as I have found no other Numerichs in any of my genealogy research (other than Richard's off-spring). Of course there are significantly more Numrichs than either Numericks or Numerichs, so my firm belief is that our roots all lie in that family spelling. In fact, when I trace back my family line, my great-grandfather Ludwig is most often documented with the Numrich spelling, though I occasionally find him with the Numerick spelling (especially his obituary). With very few exceptions, though, I find my grandfather George consistently with the Numerick spelling. Setting aside any possibility of a "deep dark family secret", I have yet to be given a satisfactory explanation of why grandpa (or maybe great-grandpa?) changed his name. In fact, the only explanation had to do with a concern back in the days of immigration of having a name that was too foreign. I'm not sure if that's really why, but it's all I have (for now). If there's anyone out there with any information that will help me solve this "mystery" please send me an email (gibrian1966@yahoo.com) or post a message.