Don Osborn wrote:

> A discussion on the Unicode list may be more appropriate here
> (appended below in chrono order). It ends up asking about the
> history of the letter K. One might equally well ask the history of C
> as it can stand for a number of different sounds in different
> languages or positions (s, k, ch, ts).

I don't know if this is what you want, however:

In the earliest Latin inscriptions, letter <C> stood for sound [g]. This is
clear if you compare the position of the letter in the Latin alphabet -- A,
B, *C*, D, E... -- with the position of <gamma> in the Greek alphabet -- Α,
Β, *Γ*, Δ, Ε... (alpha, beta, *gamma*, delta, digamma, zeta, (h)eta...). At
that time, the sound [k] was still normally spelled with <K>.

This original situation is still evident in some fossilized spellings, such
as the Roman proper name "CAIVS" ("Caius" or "Gaius"), which was pronounced
['gajus], or the noun "KALENDAE" ('first day of a month'), which was spelled
with <K> more often than with <C>.

But the Etruscan language had no [g] sound, so both <K> and <C> were used to
spell sound [k]. As <C> was graphically simpler, "K" soon went out of use,
and is rarely found in Etruscan inscriptions.

Because of Etruscan influence, also Latin <C> got to be used more and more
commonly for sound [k] so, for some time, letter <C> noted both [k] and [g].
To differentiate the two sounds, a diacritic bar was added letter to
indicate the second one, which gave our <G>.

The new letter was placed on the 7th slot in the alphabet order, in place of
letter <Z> which was at that time useless in Latin. (Later on, <Z> was
re-borrowed from the Greek alphabet to spell Greek loanwords, and it was
appended at the end of the alphabet).

So, for a certain number of centuries, Latin <C> unambiguously represented
sound [k], as can be seen by the fact that it was regularly used to
transliterate Greek <K>.

In the last centuries of the Roman empire [k] and [g] sounds followed by
front vowels [i] and [e] became palatalized. So, "CICERO", which used to be
pronounced "'kikero", became ['kjikjero] and later ['tʃitʃero] ([tʃ] = "ch"
in English "chin"); "GIGANTEM", which used to be pronounced [gi'gantem],
became [gji'gante(m)] and then [dƷi'gante(m)] ([dƷ] = English "j"). Before
back or central vowels ([a], [o], [u]) and consonants, the two letter
retained the original velar sounds.

These palatal sounds remained the same in Italian and Rumanian, while they
evolved to [ts], [s], [θ] and [Ʒ], [x] in other romance languages. Through
loanwords, the "soft" pronunciation of <C> and <G> also entered Germanic
languages, hence the initial [s] or [ts] sound of English "center", German
"Zentrum" (or "Centrum"), etc.

Some modern systems, such as pinyin or some Eastern European orthographies,
generalized the "soft" sound for <C>, generally to mark the affricate [ts].

(Disclaimer: the above explanation is totally out of my memory... It has
been written for the sole purpose of trying to defeat the current Guinness
record for the biggest number of errata generated by a single mailing list
message. :-)

_ Marco