Pronunciation of the letter "c"

Question

It sounds to me as if the the letter "c" is variously pronounced "th" or "s" or "k".  What are the rules for pronunciation of the letter "c".

Accepted Answer

Hola Tom
yes, you're right. The letter C sounds different depending on the vowel that comes after. 
C + a, o, u  sounds as [k], like in English words cat, cake, come, cucumber...
C + e, i sound as [th], like in English words the, thing, Athens...
In Spanish for example:
casa = ka-sa
coche = ko-che
cuna = ku - na
cine = thi -ne
cena = the-na
cien = thi -en
When the letter c has the sound of an s as in English words sound, Sally, soul..., this is in Latin America and some parts of Spain where people pronounce what just explained above related to the th sound but making a s sound instead of th. But this is not noticeable from the dictation because the narrator is from a part of Spain where the usual sound is th.
I hope this clarified it
Saludos
Inma