The sign is possibly adapted from an Egyptian hieroglyph for a staff sling, which may have been the meaning of the name gimel.

However, during the course of the Old English period, /k/ before front vowels (/e/ and /i/) was palatalized, having changed by the tenth century to [tʃ], though ⟨c⟩ was still used, as in cir(i)ce, wrecc(e)a.

On the continent, meanwhile, a similar phonetic change before the same two vowels had also been going on in almost all modern romance languages (for example, in Italian).

In Vulgar Latin, /k/ became palatalized to [tʃ] in Italy and Dalmatia; in France and the Iberian Peninsula, it became [ts].

Subsequently, the Latin phoneme /kw/ (spelled ⟨qv⟩) de-labialized to /k/, meaning that the various Romance languages had /k/ before front vowels.

In French, it was represented by the digraph ⟨ch⟩, as in champ (from Latin camp-um), and this spelling was introduced into English: the Hatton Gospels, written c. 1160, have in Matt.

i-iii, child, chyld, riche, and mychel, for the cild, rice, and mycel of the Old English version whence they were copied.

By the end of the thirteenth century, both in France and England, this sound /ts/ was de-affricated to /s/; and from that time, ⟨c⟩ has represented /s/ before front vowels either for etymological reasons, as in lance, cent, or to avoid the ambiguity due to the "etymological" use of ⟨s⟩ for /z/, as in ace, mice, once, pence, defence.

Hence, today, the Romance languages and English have a common feature inherited from Vulgar Latin spelling conventions where ⟨c⟩ takes on either a "hard" or "soft" value depending on the following letter.

In French, Portuguese, Catalan, and Spanish from Latin America and some places in Spain, the soft ⟨c⟩ value is /s/ as it is in English.

Norwegian, Afrikaans, and Icelandic are the most restrictive, replacing all cases of ⟨c⟩ with ⟨k⟩ or ⟨s⟩, and reserving ⟨c⟩ for unassimilated loanwords and names.

In Hanyu Pinyin, the standard romanization of Mandarin Chinese, the letter represents an aspirated version of this sound, /t͡sh/.

Yup'ik, Indonesian, Malay, and a number of African languages such as Hausa, Fula, and Manding share the soft Italian value of /t͡ʃ/.

The letter ⟨c⟩ is also used as a transliteration of Cyrillic ⟨ц⟩ in the Latin forms of Serbian, Macedonian, and sometimes Ukrainian, along with the digraph ⟨ts⟩.

Variant forms of the letter have unique code points for specialist use: the alphanumeric symbols set in mathematics and science, voiceless palatal sounds in linguistics, and halfwidth and fullwidth forms for legacy CJK font compatibility.