Many parents notice their child saying “thun” instead of “sun” or “nake” instead of “snake” and wonder if it’s something to worry about.
The “S” sound is one of the later-developing speech sounds. While some children master it early, others continue refining it throughout the preschool years.
The important question isn’t just whether your child can say “S”, but whether their speech is developing as expected for their age and whether they can be understood by others.
The short answer
Most children develop the “S” sound between 4 and 5 years of age, although there is a wide range of typical development. By the time children start school, they are usually producing “S” accurately in everyday speech.
If your child is still having significant difficulty with the “S” sound after starting school, or if they have a noticeable lisp or are difficult to understand, it is a good idea to seek advice from a speech pathologist.
Why is the “S” sound difficult?
The “S” sound requires precise coordination of the tongue, lips and airflow.
To produce a clear “S” sound, children need to:
- Place their tongue just behind their top teeth (without touching them).
- Keep the sides of the tongue raised.
- Direct a narrow stream of air through the middle of the tongue.
- Keep their vocal cords switched off (unlike the “Z” sound).
Because it requires such precise control, “S” often develops later than sounds like M, B and P.
What is typical at different ages?
Around 2–3 years
Many children are still learning how to produce “S”.
You may hear them:
- Leave the sound out.
- Replace it with another sound.
- Simplify longer words.
These patterns can be a normal part of speech development.
Around 3–4 years
Children are becoming easier to understand, but some errors with “S” may still occur.
Many children continue practising this sound through everyday conversations.
Around 4–5 years
Most children are developing a clearer “S” sound and using it more consistently.
Some occasional errors may still occur while they continue refining their speech.
Around school age
By the time children begin school, most are using “S” accurately in everyday speech.
If persistent errors remain beyond this age, an assessment is recommended.
What is a lisp?
A lisp is a speech sound disorder that affects the production of sounds such as:
- S
- Z
- Sometimes SH and CH
Children with a lisp may produce these sounds differently because of the way their tongue and airflow are positioned.
There are different types of lisps, including:
Interdental lisp
The tongue comes forward between the front teeth.
For example:
“Sun” may sound more like “thun.”
Dentalised lisp
The tongue pushes against the front teeth during speech.
Lateral lisp
Air escapes over the sides of the tongue instead of through the middle.
This often gives speech a “slushy” quality and is not considered a typical stage of development.
A speech pathologist can identify the type of lisp and determine whether therapy is recommended.
Should I correct my child’s speech?
Rather than asking your child to repeat words correctly, try modelling the correct pronunciation naturally.
For example:
Child: “I see a thnake.”
Adult: “Yes! I can see a snake too.”
This gives your child a clear example without creating pressure or interrupting the conversation.
Can thumb sucking or dummy use affect the “S” sound?
Prolonged thumb sucking or dummy use may influence oral and dental development, including the position of the tongue and teeth.
For some children, these changes may contribute to difficulties producing sounds such as “S” clearly.
However, these habits do not automatically cause a speech sound disorder, and many children who suck their thumb or use a dummy develop typical speech.
When should I see a speech pathologist?
Consider arranging an assessment if your child:
- Is still unable to produce “S” after starting school.
- Has a noticeable lisp.
- Is difficult for unfamiliar people to understand.
- Becomes frustrated when speaking.
- Avoids talking because others don’t understand them.
- You have concerns about their speech.
Early assessment can provide reassurance and identify whether therapy is likely to be helpful.
How Unified Speech Pathology can help
At Unified Speech Pathology, we assess children’s speech using evidence-based assessment tools to understand which sounds they are developing and whether their speech is appropriate for their age.
If therapy is recommended, we use engaging, play-based activities to help children learn correct speech sound production while building confidence and communication skills.
We also work closely with families, providing practical strategies to support speech practice at home.
Frequently Asked Questions
Is it normal for a 4-year-old to have trouble saying “S”?
Yes. Some children are still refining the “S” sound at four years of age. If errors continue beyond the early school years or significantly affect intelligibility, it is worth seeking advice from a speech pathologist.
Will my child grow out of a lisp?
Some speech errors improve naturally as children develop. However, certain types of lisps—particularly a lateral lisp—are unlikely to resolve without therapy.
Can braces fix a lisp?
Orthodontic treatment may improve dental alignment, but it does not teach children how to produce speech sounds correctly. Some children benefit from speech therapy before, during or after orthodontic treatment.
Do I need a referral?
No. Speech pathologists are first-contact practitioners, so you can book an assessment without a referral. If you’re eligible for Medicare or NDIS funding, we can also discuss your funding options.
References
- Speech Pathology Australia. (n.d.). Communication Milestones. Retrieved from https://www.speechpathologyaustralia.org.au
- McLeod, S., & Crowe, K. (2018). Children’s consonant acquisition in 27 languages: A cross-linguistic review. American Journal of Speech-Language Pathology, 27(4), 1546–1571.
- McLeod, S., & Baker, E. (2017). Children’s Speech: An Evidence-Based Approach to Assessment and Intervention. Pearson Australia.
- Raising Children Network. (n.d.). Speech development in children. Australian Government supported parenting resource. Retrieved from https://raisingchildren.net.au
- Centre of Research Excellence in Speech and Language (CRESL). (n.d.). Children’s speech development resources. Retrieved from https://www.cresl.com.au
Disclaimer: This article is intended for general educational purposes only and should not replace an individual assessment by a qualified speech pathologist or other healthcare professional. If you have concerns about your child’s speech development, seek professional advice.
