In Latin there is no evidence for the interchange of c with a sibilant earlier than the 6th century A.D.
In the middle of words when t precedes a palatal sound like i (y) which is not syllabic, it coalesces with it into the sound of sh as in position, nation, &c. The change to a sibilant in these cases took place in late Latin, but in Middle English the i following the t was still pronounced as a separate syllable.
The Greek name for the sibilant (clyFca) may simply mean the hissing letter and be a derivative from vi j"co; many authorities, however, hold that it is a corruption of the Phoenician Samech.
In the Phoenician alphabet a sibilant Zade (Tzaddi) stands between q and p. Hence Q is the nineteenth letter in the Phoenician alphabet, the eighteenth in the Greek numerical alphabet, which alone contains it, the sixteenth (owing to the omission of 8 and E) in the Latin, and (from the addition of J) the seventeenth in the English alphabet.
Sibilant: s (Welsh has no z).
C before e and i is represented either by the hard sibilant s or by the soft z.
Between N and 0 the Phoenician and the Ionic Greek alphabet have a sibilant - in Greek = x.
In other dialects, however, it had been palatalized to a sibilant before i-sounds some time before the Christian era; e.g.
This demonstrates beyond a doubt the possibility of a strongly palatalized n becoming a palatal sibilant or vice versa, between which utterances there is but a very slight tongue movement.
Th), Syriac has an ordinary dental t, but Hebrew has a sibilant (sh).
(2) Hebrew has one more sibilant than Arabic or Syriac: thus, as corresponding to s (samekh), s (sin) sh in Hebrew, Arabic has only s (sin) sh, while Syriac has a different pair s (samekh) sh.
The sh sound is sometimes not even written with a sibilant, as in the pronunciation of the ci and ti of words like rhetorician and nation.