Why is Castillian Spanish spoken with the thick s sound, as in hace and loscientos?

Question

Which words and sounds are pronounced that way?

Answer 1

You're referring to the pronounciation of the letters "c" (before the vowels "e" and "i") and "z". Spanish-speaking Spaniards push the tip of their tongues against the back of the upper front teeth. The sound produced is similar to "th" in "Rosenthal".

But that is not the only difference in pronounciation with Spanish as spoken in other countries:

They also pronounce the "s" as a soft "ssssh".

The pronounciation of the letter "j" is also different. They pronounce it longer and stronger. "Mi parejjjja"

They also use compound verbs more frequently. A common example is the use of the ante-presente, instead of the pasado (past) of the indicative mood for describing recent actions in the past. For example: While in Mexico we say "Me caí" ("I've fallen"), Spanish speakers in Spain say "Me he caído".

Another difference is the speed. Spaniards generally speak faster than people in Latin America.

Answer 2

I think you mean the pronuntiation of the letter "c" in Spanish. Words that get this sound for instead.
Ceniza the first "c" and the "z" it's pronounced this way.
Caza the "z". The "c" it's pronounced like you do with "k" in English
Cereza the first "c" and the "z" it's pronounced this way
Cocer "c" the second "c". The first "c" it's pronounced like you do with "k" in English.
Cerveza the first "c" and the "z" it's pronounced in this way

To sum up. We pronounce the "c" sound in lots of words which have letter "c", before the vowels "e" and "i" and all words which have letter "z". "Z" in English is pronounced diferent way we do in Spanish.