Regular readers will know by now that I am engrossed in Nicholas Ostler’s* biography of Latin, Ad Infinitum. I’m still only about halfway through the book, but I’ve already learned a great deal — a good sign for any book! I’ve been dropping post-it notes onto pages for some time now with an eye to composing a post or two (or half a dozen, more than likely), and this is the first of them. These posts, I hope, won’t be your run of the mill notes (like speculating on the origins of that old saw, “mind your P’s and Q’s”), but rather a series of interconnected and generally pretty arcane points — the sort of thing I love. Feel free to drop me a line with feedback.
So, to business. Ever wondered why we have the letters C, K, and Q, when all three originally represented basically the same sound? (Certainly in Classical Latin, they did. And for that reason, the Romance languages that developed from Latin didn’t always inherit all three letters — often losing the K.) I’ve definitely wondered about this, and Ostler provides an answer. 
It appears that each letter was used in connection with a different following vowel, a practice Latin borrowed from Etruscan (to which early Latin owed a great deal). Proper usage dictated that K was used before A, Q before U, and C otherwise. That would be interesting enough on its own, but here’s the part I found most interesting: this explains why in English we call these letters cee, kay, and cue. Look at the vowels! An ancient orthographical rule of the Etruscans — a people extinct for well over a millennium — still persists in English today! I would add that, far earlier, the names of the letters in Latin showed the same pattern (cē, kā, qū), and likewise in the emerging vernacular of the Middle Ages. Therefore we have French (cé, ka, cu), Spanish (ce, ka, cu), Italian (ci, kappa [a borrowing from Greek, but the pattern nevertheless holds], cu).
And then there is the case of Romanian. Whereas some of the Romance languages lost the K, Romanian initially had no use for the Q. The other two letters followed the Etruscan pattern and were called ce, ka. Here’s the interesting thing: the Q was officially reintroduced into Romanian late in the 20th century (in 1982, to be exact), though it was in use for some time before that date — only in loan-words from other languages. What did they name the letter? Turns out it was kü (or chiu), which bears out the same Etruscan pattern! (Though in the case of this late addition, the letter name was probably driven by that of other Romance languages and not with any specific awareness of the underlying reason.)
The pattern breaks in the Portuguese Q — cê, cá [or cappa, ditto my note on Italian], but quê. I wonder why. I would strongly suspect Berber or Arabic influence, but if that were the case, why wasn’t Spanish affected?
* Ostler is a pretty interesting surname, actually. In fact, ostler is an ordinary English word, though an archaic one. An ostler is basically an innkeeper — Tolkien uses the word in this sense in his poem, “The Man in the Moon Stayed Up Too Late” (The Lord of the Rings and The Adventures of Tom Bombadil) — though in another sense, it was more specific: the man who took care of the horses at the inn. An alternate spelling, hostler, belies its kinship with hostel, hotel, hospitable, and even hospital.
 Ostler, Nicholas. Ad Infinitum: A Biography of Latin. New York: Walker & Co., 2007, p.59 footnote.