Speech and language
Lisps in Children
Four types, and only some resolve on their own — plus the home 'help' that makes it harder.
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A lisp is a difficulty producing the "s" and "z" sounds, and the type matters more than most parents are told. An interdental lisp — where the tongue comes between the teeth, producing a "th" sound — is a normal part of speech development in young children and commonly resolves on its own. A lateral lisp is different: air escapes over the sides of the tongue producing a wet or slushy quality, it is not part of typical development at any age, and it does not resolve without therapy. That distinction is the single most useful thing to know, because one type warrants patience and the other warrants an appointment.
What is a lisp?
A lisp is a difficulty producing the "s" and "z" sounds. The sounds are made by channelling air down a narrow groove in the middle of the tongue, and a lisp happens when the tongue sits somewhere else — forward, or to one side.
"S" is one of the later sounds to settle in typical speech development, which is why lisps are common in young children and why age alone is a poor guide to whether one matters.
The four types
Interdental lisp — the common one
The tongue comes forward between the teeth, and "s" comes out as "th" — "thun" for "sun". This is a normal part of speech development in young children, it is especially common while front teeth are missing, and it usually resolves.
Lateral lisp — the one that does not resolve
Air escapes over the sides of the tongue instead of down the middle, producing a wet or slushy quality. This is not part of typical development at any age and it does not resolve on its own.
Dentalized lisp
The tongue pushes against the back of the front teeth rather than through them. It produces a muffled "s" and is a milder version of the same forward placement.
Palatal lisp
The tongue makes contact further back, against the roof of the mouth. It is the least common of the four.
Which lisps go away on their own?
Interdental and dentalized lisps commonly resolve without treatment; lateral and palatal lisps generally do not. That is the whole of the practical distinction, and it is worth knowing before deciding whether to wait.
How can I tell which type my child has?
Listen for where the air is going. If you can see the tongue between the teeth and the sound is a clean "th", that is an interdental lisp. If the sound is wet, slushy, or spread out — as though it is coming from the sides of the mouth — that is a lateral lisp.
A useful test: ask your child to say a long "sssss". An interdental lisp produces a clear "th" sound. A lateral lisp sounds messy and wet, and often looks it too.
| Type | What you hear | Resolves on its own? |
|---|---|---|
| Interdental | "S" sounds like "th"; tongue visible between the teeth | Usually |
| Dentalized | Muffled "s"; tongue against the back of the teeth | Often |
| Lateral | Wet or slushy; air escaping over the sides | No — needs therapy |
| Palatal | "S" made further back, against the roof of the mouth | No |
What causes a lisp?
Frequently there is no identifiable cause, and a lisp is usually about tongue placement rather than structure.
Does thumb sucking cause a lisp?
Prolonged thumb sucking and pacifier use can contribute, because sustained pressure affects how the front teeth and palate develop, and that changes where the tongue has to go. It is a contributing factor rather than a cause on its own. → Pacifier use, teeth, and speech
Does tongue tie cause a lisp?
Sometimes it contributes, but most lisps are not caused by tongue tie. A restricted tongue can limit the movements a sound needs, and a speech-language pathologist can tell you whether structure is playing a part in your child's case. → Tongue ties
Do teeth and bite affect it?
Yes, and missing front teeth are the most common example. An open bite or a crossbite changes the space the tongue is working in, which can produce or maintain a lisp. → Early signs of bite problems
What speech therapy involves
Therapy for a lisp is placement work: teaching where the tongue goes, and then practicing the sound in progressively harder contexts — the sound alone, then in syllables, words, sentences, and finally conversation.
A speech-language pathologist will usually start by finding a way to produce the sound correctly even once, then build from there. Lateral lisps generally take longer than interdental ones, because the pattern is not one the child will drift out of.
What not to do at home
- Do not correct repeatedly in conversation. It rarely changes the sound and it does make a child self-conscious about talking.
- Do not ask a child to "say it properly". If they could, they would.
- Do not attempt tongue exercises found online. Placement work needs to be taught correctly, and practicing a wrong placement makes it harder to change.
What does help is ordinary conversation, plenty of it, and not making the sound the subject of it.
Frequently asked questions
What is a lisp?
A difficulty producing the "s" and "z" sounds, usually because of where the tongue sits during the sound. There are several types, and which type it is determines whether it is likely to resolve on its own.
What is a lateral lisp?
A lisp where air escapes over the sides of the tongue rather than down the middle, producing a wet or slushy sound. It is not part of typical speech development at any age, and it needs speech therapy.
Does tongue tie cause a lisp?
Sometimes it contributes, but a lisp is usually about where the tongue is placed rather than how it is attached. A speech-language pathologist can tell you whether structure is playing a part.
Which lisps go away on their own?
Interdental lisps — where the tongue comes forward between the teeth and "s" sounds like "th" — are common in young children and usually resolve. Lateral lisps do not resolve on their own at any age.
Should I correct my child's lisp at home?
No. Repeated correction in conversation tends to make a child self-conscious without changing the sound, and practicing a wrong tongue placement makes it harder to change later. Placement work needs to be taught properly.
Should I correct my child's lisp at home?
Not by asking them to repeat the sound, which is the instinctive move and the least useful one. A lisp is a motor pattern, and repetition without the right placement cue mostly rehearses the pattern. What helps at home is modeling the word correctly in your own reply and moving on, so the child hears the target without being put on the spot. The placement work belongs in therapy.
When should we see a speech-language pathologist?
If you can hear a wet or slushy quality, arrange an appointment rather than waiting. For an interdental lisp, it is reasonable to raise it if it is still there once the front adult teeth are in, or sooner if it bothers your child.
My child has a lisp and is losing their front teeth. Is that the cause?
Missing front teeth commonly produce a temporary interdental lisp, and it usually settles once the adult teeth are in. A wet or slushy quality is a different matter and is not explained by missing teeth.
Sources
- American Speech-Language-Hearing Association. Practice portal: speech sound disorders in children. Checked August 19, 2026.
- Lee ASY, Gibbon FE. Non-speech oral motor treatment for children with developmental speech sound disorders. Cochrane Database of Systematic Reviews. 2015;(3):CD009383. doi:10.1002/14651858.CD009383.pub2 (PMID 25805060)
Disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified professional about your own child.