When to Pronounce S and Z Sounds in English

S and Z are very common sounds in English.  Typically, we pronounce the S sound when you read a letter S and a Z sound when you read the letter Z. 

But, (isn’t there always a “but” with English reading and pronunciation?) the letter S is often pronounced as a Z sound.  Yes, you read that correctly, the letter S is often pronounced as a Z sound. This leads to many mispronounce words.  

How do you know what to say?  Here are a few quick rules to follow: 

Say the Z sound when you see a letter Z.
Pronounce the letter S as a Z sound when the S is between two vowels like in the words cousin, music, and reason. 
Pronounce verbs ending in a SE then silent E as the Z sound.  You hear this in arouse, appease, choose.
Pronounce verbs ending in a SE (silent e that makes the vowel long) as the Z sound.  You hear this in the words these, those, phrase.
Pronounce the -S at the end of a word as the Z sound if the root word ends in a voiced sound.  This is the case in tabs, pans, and Ken’s. 
Pronounce the -S at the end of a word as IZ if the root word ends in a strident or hissing sound like S, SH, CH, J.  This is the case in misses, wishes, church’s, and judges.  
Memorize common function words that have the letter S pronounced  as a Z.  This is the case in the words is, has, was, his.   

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