Open a dictionary and check the pronunciation of music, easy, or please. Every single one contains a /z/ sound, even though the spelling shows S. This is the intervocalic S voicing pattern, and learning to expect /z/ in the right places will instantly make your spoken English sound more natural.
The Rule
When the letter S appears between two vowel sounds — especially after a stressed vowel — it is pronounced /z/, not /s/. The voicing of the surrounding vowels spreads to the consonant.
- easy → /ˈiːzi/
- music → /ˈmjuːzɪk/
- busy → /ˈbɪzi/
- choose → /tʃuːz/ (the oo counts as a vowel sound next to the S)
Practice: S-to-Z Words
Important Exceptions
The rule is strong but not absolute. S stays /s/ when:
- It starts a new morpheme or compound: bedside, newsstand (two Ss stay /s/).
- It follows a Latin prefix like re-, pre-: research, present (noun) are often /s/.
- In some learned words: basic /ˈbeɪsɪk/, crisis /ˈkraɪsɪs/, philosophy /fɪˈlɒsəfi/.
The Noun-Verb Split
Some words change meaning based on /s/ vs /z/:
- use (noun) /juːs/ — the purpose of something.
- use (verb) /juːz/ — to employ something.
- Same for close, house, advice/advise, excuse.
Why This Matters
If you say /s/ in music, please, or easy, natives may hear a slight strangeness. Worse, your ear won't be tuned for /z/, and you'll miss the subtle voiced vs voiceless contrast that carries real meaning.
Practice Tip
Put your fingers on your throat and say /s/. No vibration. Now say /z/. You'll feel vibration. Run through ten S-between-vowels words making the throat buzz. Your /z/ will become automatic.