Hard and soft C

In the Latin-based orthographies of many European languages, including English, a distinction between hard and soft ⟨c⟩ occurs in which ⟨c⟩ represents two distinct phonemes. The sound of a hard ⟨c⟩ often precedes the non-front vowels ⟨a⟩, ⟨o⟩ and ⟨u⟩, and is that of the voiceless velar stop, /k/ (as in car). The sound of a soft ⟨c⟩, typically before ⟨e⟩, ⟨i⟩ and ⟨y⟩, may be a fricative or affricate, depending on the language. In English (and not coincidentally also French), the sound of soft ⟨c⟩ is /s/ (as in both ⟨c⟩s in "circumference").

There was no soft ⟨c⟩ in classical Latin, where it was always pronounced as /k/.