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Most children say a clear S by about age 5, according to Alberta Health Services. Before that, a lisp is common enough that many speech-language pathologists would call it ordinary. The trouble is that not every lisp is the ordinary kind, and parents can’t always tell which one they are hearing.
Speech and Hearing BC says a frontal lisp, where the tongue pushes forward on S and Z, is common up to about 4 to 4½ years (Speech and Hearing BC). That is a useful benchmark. After it, the question changes from “will they grow out of it?” to “what is keeping it there?”
Below are the four main types of lisp, the causes Canadian health sources name, and the point at which treating a lisp makes more sense than waiting.
What is a lisp in a child?
A lisp is a speech sound error that affects S and Z. AHS describes it as an S that does not sound clear, such as “soap” coming out like “thoap”. Speech-language pathologists treat it as a question of tongue placement and airflow: where the tongue sits, and where the air goes, when the child tries to make a hissing sound.
Is a lisp a speech disorder?
It depends on the age and the pattern. In a four-year-old, a frontal lisp is a developmental difference, one of the sound errors the AHS chart expects to fade. When the same lisp is still there well past the age by which most children have a clear S, speech-language pathologists treat it as a speech sound disorder. A lateral lisp is treated that way from the start.
A lisp is one piece of the wider picture of sound development. For the full timeline for S, R, and TH, see our guide to speech sound milestones by age
What are the four types of lisp?
Clinicians usually describe four patterns, grouped by where the tongue and air end up.
| Type | What you hear | What to know |
|---|---|---|
| Frontal (interdental) | S sounds like “th” because the tongue pushes between the front teeth | Common in younger children, up to about 4 to 4½ years |
| Dentalized | S sounds muffled because the tongue presses against the front teeth | Can appear in young children; worth checking if it lingers |
| Lateral | S sounds wet or slushy because air escapes over the sides of the tongue | Not an expected stage; get it assessed at any age |
| Palatal | S sounds closer to “sh” because the tongue sits too far back | Not an expected stage; get it assessed |
Of the four, the frontal lisp is the one most children grow out of. Lateral and palatal lisps usually do not fix themselves, which is why many speech-language pathologists do not recommend waiting on them.
How can you tell which lisp your child has?
Listen first. Does the S sound like a soft “th”? Does it sound wet, as if there is water in the mouth? Does it lean toward “sh”? Then watch. Ask your child to say “sun” or “soap” in front of a mirror and see whether the tongue shows between the teeth. That gives you something concrete to describe, but it does not replace an assessment, because the types can overlap and a child can have more than one.
What causes a lisp in a child?
For many children no single cause turns up. Where one does, Canadian sources name a few.
Tongue thrust
Babies swallow with the tongue pushed forward, and most children move to a more mature pattern as they grow. In some, the tongue keeps pushing forward during speech or swallowing. Speech and Hearing BC says this pulls sounds normally made behind the teeth, including S and Z, forward through them, and lists thumb sucking, enlarged tonsils and adenoids, and allergies as possible causes. It recommends a check with a doctor for underlying health issues, and notes that prolonged tongue thrust can change how teeth grow in, so older children may need orthodontics as well.
Tongue-tie
Parents often hear tongue-tie blamed for lisps. The evidence is thinner than the confidence. A review in the Canadian Medical Association Journal said there is no evidence that ankyloglossia causes articulation problems, that definitive studies on speech are lacking, and that an assessment by a speech pathologist can guide non-invasive options (CMAJ). More recently, the president of the Canadian Academy of Pediatric Dentistry told a Canadian Dental Association publication that tongue-tie can affect speech in some children, but that sometimes doing nothing is the best option Canadian Dental Association. A lisp alone is not proof of a tongue-tie.
Teeth and hearing
Missing front teeth, braces, and gaps can change how S sounds for a while. Hearing is worth ruling out too, since a child who hears sounds poorly will tend to learn them poorly.
At what age does a lisp go away on its own?
For a frontal lisp, the realistic window runs to about 4½ or 5. Speech and Hearing BC puts the common range at up to 4 to 4½ years, and AHS says most children say S correctly by 5. A frontal lisp that is still there at five is no longer on the usual schedule. Lateral and palatal lisps are not part of the typical pattern, so waiting for them to resolve rarely makes sense.
When should a lisp be treated?
Treat sooner rather than later when any of these apply:
- The lisp sounds wet or slushy (lateral), or the S sounds like “sh” (palatal), at any age
- A frontal lisp continues beyond about age 5
- You can see the tongue between the teeth at rest, the child breathes through the mouth, or the front teeth do not meet when the mouth is closed
- The child is frustrated, avoiding talking, or being teased about the way they speak
Speech-Language & Audiology Canada makes the broader point in its submission to the federal Finance Committee: the earlier a communication problem is identified, the better the chances for improvement. For a lisp, starting early usually also means less time for the habit to settle in.
What does lisp treatment involve?
According to Speech and Hearing BC, a speech-language pathologist starts with an oral motor assessment of lip and tongue movement, plus a speech sound assessment. The pathologist checks whether the child can make the sound correctly when shown how, and whether the child wants to change, which matters because correcting a tongue pattern is hard work for a child. Treatment then retrains the tongue so the tip rests on the ridge behind the teeth, and teaches the sounds so that “sum” and “thumb” sound different Speech and Hearing BC.
That work lines up with articulation therapy for S and Z, and a speech assessment is where it starts. Because so much of lisp therapy is watching and copying tongue placement, some families do it through online speech therapy. A speech-language pathologist can tell you whether your child is a good fit for video sessions. How quickly a lisp improves depends on its type, how aware the child is of the error, and how often they practise between sessions, so ask for a rough timeline after the first assessment instead of expecting a fixed number of weeks.
At home, AHS suggests short “sound activities” for younger children: point out the S in words during play and books, and give the sound a name such as the snake sound. A relaxed model of the right sound works better than constant correction.
Can you fix a lisp at home?
Parents can do a lot to support a lisp, but fixing one is a different job. Short, playful practice is fine: noticing S words in books, saying them clearly, and letting your child hear the difference. Formal tongue exercises are better guided by a speech-language pathologist, because the right tongue position depends on which type of lisp the child has. A pattern practised the wrong way tends to stick.
Who pays for lisp therapy in Canada?
It depends on the province and the child’s age. Ontario’s Preschool Speech and Language Program is free and needs no doctor’s referral for children from birth to school entry York Region listing. In British Columbia, the Medical Services Plan does not cover private speech, language, or swallowing therapy, and Speech and Hearing BC points families to extended health plans and, for eligible children, Ministry of Children and Family Development funding Speech and Hearing BC. For school-age children, the Canadian Stuttering Association notes that government-funded speech services exist in most provinces, so the school’s speech-language pathologist is a sensible first call. Private insurance plans also carry a yearly maximum, so it is worth checking yours before booking a block of sessions Canadian Stuttering Association.
Next steps if you’re worried about your child’s lisp
Start by working out which kind of lisp you are hearing. If the S sounds like a soft “th” and your child is under about 4½, there is usually no need to worry yet. Keep modelling clear S sounds during play and reading, and check back in a few months. If the S sounds wet or slushy, or leans toward “sh,” don’t wait for it to pass. Those patterns are not an expected stage, and an assessment is worthwhile at any age.
A frontal lisp that is still there at 5 is also worth acting on. By then it is no longer a matter of “will they grow out of it?” but of what is keeping it in place, and a speech-language pathologist can answer that. If you can see your child’s tongue between the teeth at rest, if they breathe through their mouth, or if they have started avoiding speaking because of the way they sound, book the assessment sooner rather than later.
You don’t need to arrive with a diagnosis. Bring what you have noticed: when you first heard the lisp, which words it shows up in, and whether it changes when your child is tired or excited. That gives the pathologist a good starting point, and it makes the first appointment much more useful. A hearing check and a dental check are sensible companions to the assessment, since both can affect how S sounds.
Above all, treat the lisp as something that can be changed. With the right guidance, regular short practice, and a calm, encouraging approach at home, most children make steady progress. Early support also tends to spare them months or years of frustration, which is often the real cost of waiting.
Ready to book an assessment?
If your child’s lisp is lateral, palatal, or still present past age 5, or if it is affecting their confidence, the next step is a speech assessment. A speech-language pathologist can identify the type, check for contributing factors like tongue thrust or hearing, and set out a clear plan. Reach out to a certified speech-language pathologist in your province, or ask your child’s school about its speech services, and get a baseline sooner rather than later.
Frequently asked questions
1. Should I correct my child every time they lisp?
No. Constant correction can make a child self-conscious about speaking. Instead, repeat the word back naturally with a clear S, for example, “Yes, the soap is in the bath,” and save focused practice for short, playful sessions.
2. Can a lisp come back after it has been corrected?
It can, especially if the underlying tongue habit has not fully settled. Your speech-language pathologist can tell you how to keep the new pattern steady, and a short check-in after therapy ends is reasonable.
3. Do adults still have lisps?
Yes. A lisp that was never treated in childhood can continue into adulthood, and adults can work on it with a speech-language pathologist too. It is easier to change early, but it is never too late to ask.
4. Is a lisp a sign of a bigger problem?
Usually not. A lisp is typically an isolated speech sound pattern. If your child has other difficulties, such as trouble being understood in general, delayed language, or feeding problems, mention them at the assessment so the full picture is considered.
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