Here's a cool thing I learned a few months ago: Have you ever wondered about the prevalence of words in English spelled with an O but pronounced as if it were U; words like "son", "money" (and "honey"), "love" (and "dove"), "wonder", "London", and I suspect once upon a time, also "coney"*
? What they all share in common is that the O is next to an M, N, V or W; and the reason for this spelling is that when a U is juxtaposed to one of these letters in Carolingian miniscules, it becomes very difficult to tell which letter is which, as is famously shown by writing the word "minimum" in miniscules:
Consequently, the spelling of the English words was changed to use an O instead of a U, which made life easier for readers a thousand years ago, though more difficult for people trying to learn English spelling. It's amazing how much insight knowing this has given me on English spelling; I keep coming across more and more words the spelling of which this explains.
* "Coney" used to be in general use in English to mean "rabbit". (The German for "rabbit", Kaninchen
, rendered piecewise into its English cognates, comes out as the cutesy "coneykin".) But when in the nineteenth century "cunny" arose as slang for "c*nt", which was the pronunciation at the time of "coney", the latter dropped out use, despite an attempt to rescue it by pronouncing it the way it was written, in favour of the term "rabbit", originally meaning a young rabbit.
On a similar subject, I recently discovered from the History of English podcast the reason why we have in England, counties and countesses but not counts. These terms were brought into English from Norman French after the Norman Conquest, displacing the older English terms, but "count" never quite managed to displace "earl" because its pronunciation was too much like "c*nt". I reckon at the time, the former would have had the vowel in "food" and the latter the vowel in "good", making them more similar than they are today.
I wonder if there are any other words that resemblance to taboo words forced out of the language...