I was recently involved in answering this question:
Which asks whether "renumeration" or "remuneration" is correct in terms of repaying someone. Over the course of answering it appeared that remuneration is by far the more prevalent in literature (reference), but, anecdotally at least, more people than not had expected "renumeration" to be the "correct" version.
It appears that what we have here is a word that has two spellings, one of which is commonly used when spoken, but rare in literature, and the other rarely spoken, but commonly used in formal literature. It's not just that the word is mispronounced when spoken (like Wednesday for instance), it's actually "spelled" differently.
Is this more common than I think it is? Are there any other cases where this happens? Is it possible to explain why This has happened, or have I suffered from too small a sample space and remuneration is actually the more common in spoken language as well?