When is 's' pronounced as 'z'?

The attached file unveiled when the letter 's' is pronounced as 'z'. I've summarised my findings on page 1. You might find it difficult to understand on your screen. I'd strongly suggest you print out page 1 and read it along with the other pages.

I've highlighted some words in the content, for example:

consist, insist, persist, subsist (the first 's' is pronounced as 's')

desist, resist (the first 's' is pronounced as 'z')

They almost have the same spelling, but are pronounced differently.

If you find my findings a bit heavy going, it's just because you haven't yet learned International Phonetic Alphabet (IPA). There're many other questions about English which many teachers don't know how to explain to their students. But if you've learned IPA, you'll find that the answers have actually been there all the time. For example, why do we say:

a European country

an early morning

Why do we write:

preferred

preference

And why should we use the article 'an' instead of 'a':

an 'f', an 'h', an 'm' ...

but a 'u'

Why do people say:

"Mum's the word", but not "Dad's the word"?

It all comes down to their pronunciation which can be explained by IPA very simply. Hope you'll join me one day to learn more about IPA and can speak really like a native.