El Castellano
Warlord
Here explain why the difference between s and z/c are only given in Spain, with the explanation that it is the "ceceo" and "seseo" and where they are spoken:
http://spanish.stackexchange.com/qu...diferencia-entre-s-y-z-c-solo-se-da-en-españa
http://spanish.stackexchange.com/qu...diferencia-entre-s-y-z-c-solo-se-da-en-españa