Speech Sound Guide
The /z/ sound typically develops by age 5. This guide covers when /z/ develops, what typically goes wrong, simple ways to practice it, and over 85 /z/ words organized by position.
Developmental norms — when the /z/ sound typically emerges and is mastered.
Source: McLeod & Crowe (2018); Crowe & McLeod (2020), AJSLP.
A child still substituting or distorting /z/ after age 5 is a good candidate for a speech-language evaluation — earlier if they're hard to understand or frustrated.
Sound Safari's 24-sound screener checks against the McLeod & Crowe norms above.
What typically goes wrong — and whether it's age-appropriate.
/z/ → /d/
Typically resolves on its own by around age 4; worth a check-in if it persists.
What helps →
Stretch /z/ as a long buzzy "zzzz" — /z/ is a fricative (held), /d/ is a stop (quick tap). Show the smile-and-teeth position used for /s/, then turn on the voice.
/z/ → /s/
Typically resolves on its own by around age 4; worth a check-in if it persists.
What helps →
Touch the throat — /z/ buzzes, /s/ is silent. Have the child feel the vocal cord vibration on each /z/.
Practical starting points for parents and SLPs. Always follow your SLP's plan if your child is in therapy.
Every word from the Sound Safari practice library. The /z/ in each word is bolded.
Minimal pairs differ by a single sound — the heart of phonological therapy. Tap a card to hear it, or tap “vs” to hear a pair back-to-back.
More /z/ minimal pairs — tap a contrast to explore
/z/ at the start · 2
/z/ in the middle · 7
/z/ at the end · 4
Most children produce /z/ correctly by age 5. About half can do it by age 4. /z/ develops alongside /s/.
Both patterns (devoicing to /s/, stopping to /d/) are developmentally typical up to about age 4. If they persist past age 5, an SLP check-in is worthwhile.
/z/ requires the same precise tongue position as /s/ PLUS sustained voicing. Children who can do /s/ may still drop the voice (saying /s/) until they learn to maintain it.
Start with their /s/ position, then turn on the voice — touch the throat to confirm the buzz. Use minimal pairs (zoo/sue) to train voicing.
If /z/ is being replaced with /s/, /d/, or has a lateral hiss past age 5, see an SLP.
Yes — /z/ is highly treatable at any age. If /s/ is in place, adding voicing is usually straightforward.
Sounds that pair, contrast, or are commonly confused with /z/.
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