How to pronounce the letters S/Z in European Spanish? (With IPA and examples)

We are going to learn the pronunciation for the letters 'S' and 'Z' in European Spanish and we are going to use a little bit of IPA.

The letter S is always pronounced with the sound /s/. Some examples are: casas, salsas, casar
And the letter Z is also pronounced the same as the letter C, with the sound /θ/. Some examples are: zapato, capaz, cazuela, cazar, azúcar,

Please pay attention to the pronunciation of the letter Z as it changes from region to region. It also can create some spelling problems as it uses the same sound as C.

Note: There is a version of this video in Spanish.