Speech sound guide · /z/ as in “zoo”
My child can’t say the Z sound
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The short answer
Z is the voiced partner of S, made the same way with the voice switched on. In a large review of US studies, 90% of children said Z correctly by about 4 years 9 months. Children who lisp on S usually lisp on Z too.
Most children say it by about 4¾ (90% by 4 years 9 months)
How the Z sound is made
Like S, the tongue tip sits just behind the top front teeth and sends air down the middle of the tongue, but the voice buzzes at the same time. Try putting a hand on your throat: you’ll feel Z buzz and S not.
Common ways children say it differently
- A “th” lisp
- “thoo” for zoo. Usually goes along with a lisp on S.
- Uses S instead of Z
- “sip” for zip. The voice stays off.
What the age means, and what it doesn’t
“90% by 4 years 9 months” means that in the pooled studies, nine in ten children said Z correctly by that age. About one in ten children who are developing typically get there later, so it’s a guide for when to ask, not a deadline. Ages come from US children learning English.
When to ask a speech therapist about Z
- Your child is past about about 4¾ and still swaps or distorts Z.
- People outside the family often find your child hard to understand, or your child is frustrated or teased about how they talk.
- You’re worried. You don’t need to wait for a set age to ask.
More signs: Does my child need speech therapy? In the US, you can ask for a free speech evaluation, or find a certified SLP through ASHA ProFind.
Z practice words
At the start
zoo, zip, zebra, zero
In the middle
lizard, puzzle, busy, easy
At the end
buzz, nose, cheese, eyes
Use the words your child’s SLP picks first. For keeping practice low-pressure, see how to help at home, and for why a sound can work in sessions before it shows up in conversation, see carryover.
Questions parents ask about Z
When should a child say Z correctly?
In the 2020 review of US studies, 90% of children said Z correctly by about 4 years 9 months.
Should we practise S and Z together?
Often, yes: they’re made the same way. Your SLP may start with whichever is easier for your child.