Regular patterns emerge in the naming of Latin letters:
- Vowels are named entirely by their phoneme (eg. ā, ē, ū, etc.)
- Plosive letters methodically terminate in ē (eg. bē, gē, tē, etc.)
- Letter-names of fricatives & affricates begin with short e (eg. ef, el, em, etc.).
- Most recent Greek borrowings, hy and zēta, disobey the more ancient pattern.
Ecce cē, kā, qū que...
Note the 'three kays' of the Latin alphabet which represented the same sound /k/: cē, kā and qū . What's more, the Roman 'q' was restricted to positions before 'u'. This habit was borrowed from Etruscan which in its oldest stages chose 'k' before 'a', 'q' before 'u' and 'c' everywhere else. Many take these arcane rules for granted but in attempting to solve this mystery, we should also be aware that these same spelling rules were even in effect among early Greeks who used the equivalents gamma, kappa and koppa respectively. The earliest Greeks likewise restricted koppa to positions before /o/ and /u/, kappa elsewhere.
After much thought, I realized that the rule must be motivated by the very names of these letters. Look again at the Greek pair kappa and koppa. Since Semitic /q/ was an exotic sound to Greeks, the functionality of koppa (= Semitic qoph) was modified to convey non-aspirated /k/ just like kappa. To justify the usage of both however, the first syllable of the letter-name koppa must have inspired its eventual restriction to positions neighbouring back vowels in Greek before fading into oblivion.
Yet for Etruscan scribes, the merger of phonemic contrasts seen in the Semitic alphabets extended further since voiced /g/ was also a foreign sound to them. A confusing trifold representation of Etruscan /k/ by the three former Semitic letters (gimel, kaph and qoph) was the result. Like Greek but more extensive, a spelling rule seems likely to have been based rather trivially on the first syllable of each of these letter-names. This would help us reconstruct the native Etruscan letter-names for these 'kay' letters.
Refining the reconstruction of Etruscan letter-names
Using Greek and Semitic letter-names as guide, together with this odd spelling rule, I now find myself reasoning that Etruscans had originally called 'c', 'k' and 'q': *cimla, *capa and *cupa. In this way, the first syllables of each (ie. ci-, ca- and cu-) serve as fine basis for the attested spelling rules of Old Etruscan while simultaneously providing an elegant etymology for Latin cē, kā and qū. In other words, when the Romans simplified the Etruscan alphabet names, they simply clipped them down to their first syllable and used them doubly as spelling mnemonics.
This devilishly implies separate sources of the Etruscan and Greek alphabets since the required vocalism in *cimla is less like Greek gamma and more faithful to its Modern Hebrew counterpart, gimel. This suggests that Etruscans didn't adopt their alphabet from the Greeks but instead gained the alphabet more directly somehow, directly from West Semites in Asia Minor rather than Euboea perhaps.
 Bonfante/Bonfante, The Etruscan language: An introduction (2002), p.75 (see link). Here, the spelling rule is mentioned but the authors leave out any further explanation.
 Woodard,Greek writing from Knossos to Homer: A linguistic interpretation of the origin of the Greek Alphabet and the Continuity of Ancient Greek Literacy (1996), p.161 (see link); Threatte, The Grammar of Attic Inscriptions: Phonology (1980), p.21 (see link).
 I had reconstructed *camla in previous entries but I reckon that the spelling-rule argument will justify *cimla in its stead.
 Hamilton, The origins of the West Semitic alphabet in Egyptian scripts (2006), pp.57 & 283 admits to variants for this Semitic letter name: *gaml-/*giml-. (see link).
 Bonfante, The Etruscan language: An introduction, 2nd ed. (2002), p.52: "On the other hand, the Etruscan alphabet also seems to preserve the traces of a very early Greek alphabet, older in part than the split between 'Western' and 'Eastern' Greek alphabets, since it preserves all three Phoenician sibilants, the signs samekh, sade, and Sin [...], which neither 'Western' nor 'Eastern' Greek alphabet possesses any longer [...]." (see link).