Lisp in Children: When Is It a Cause for Concern?

A lisp in children usually means the child pushes their tongue between their teeth and produces the "s" and "z" sounds unclearly. Up to age 4, this is mostly a normal stage of development. But a clear lisp that continues after age 5 needs an assessment, because the habit tends to become fixed after this age.

What Is a Lisp in Children?

A lisp is a difference in how speech sounds are made, caused by the tongue pushing forward between the teeth. In the specialist literature, this is called interdental articulation, or an interdental lisp.

The problem usually shows most clearly on the "s" and "z" sounds, so "sun" can sound like "thun" and "zoo" like "thoo". The "sh" and "ch" sounds can be affected by the same error too. If your child is learning Turkish and English together, the lisp usually affects the same sounds in both languages. It can stand out more in Turkish, which has no "th" sound. Your child knows the word, but makes the sound in the wrong place in the mouth.

A child with a lisp has no difficulty with vocabulary or building sentences. Only the place where one sound is made has shifted, which makes speech harder to understand. For the developmental timeline, see our post on language development milestones from 0 to 6.

A lisp is not a problem with intelligence or grammar. In fact, ASHA describes speech sound disorders separately from language delay.

The 2 Types of Lisp

In practice, we see two different types of lisp. The difference matters a lot, because the therapy plan depends on it.

A lateral lisp does not correct itself. So speak to a specialist as soon as you notice this type. With an interdental lisp, waiting for a while is enough for most children.

At What Age Is a Lisp Normal?

Speech sounds usually develop along a predictable timeline. Below we compare what to expect at each age and what we suggest you do.

The ages in the table are averages. But do not wait for this timeline with a lateral lisp. Also, if your child is bothered by their own speech, get in touch whatever their age.

4 Causes of a Lisp

The cause of a lisp is not the same in every child. So our specialist first identifies the cause, then builds the plan.

1. Habit-Related Causes

Using a dummy or bottle for a long time, or thumb sucking, changes where the tongue rests. The tongue gets used to sitting forward, so the "s" sound comes out between the teeth.

2. Structural Causes

Differences such as a tongue tie or an open bite directly affect the sound. In this case, our specialist plans therapy together with the dentist. The order of treatment depends on the child.

3. A Learned Habit

In some children, no structural cause is found. The child has simply learned the wrong way to make the sound. This group responds fastest to therapy.

4. Difficulty Hearing the Difference

The child cannot tell the correct and incorrect sound apart by ear. That is why the first step of therapy is always listening work. Past ear infections can make this difficulty worse.

Length of Therapy by Type

The length of therapy depends on the cause and the type. Below we compare four profiles side by side.

The lengths in the table are averages. Regular home practice shortens the time in every row. For our work on the voice and speech sounds, see our voice disorder therapy page.

Which Signs Need an Assessment?

Not every sound error needs therapy. But the signs below always call for a specialist's opinion.

• Your child is over 5, but the lisp is still clear.
• The sound is slushy and lateral, so it is not expected to correct itself.
• People outside the family, such as a neighbour or teacher, find your child hard to understand.
• Your child avoids talking, for example by not putting their hand up in class.
• Other children make fun of your child's speech.
• Many sounds other than "s" are also unclear.

If even one of these applies, book an appointment. Therapy that starts early takes much less time.

The Effect of Dummies and Thumb Sucking

Using a dummy after age 2 clearly increases the risk. The tongue stays forward all the time, so it never learns the right position.

Thumb sucking has the same result. Long-term sucking also pushes the front teeth outwards, which creates an open bite. Our post on thumb sucking and nail biting explains strategies for stopping.

Once the habit stops, the sound corrects itself in some children. But after age 5, the chance of this drops quickly.

How Much Do the Teeth and Jaw Matter?

Tooth structure alone does not cause a lisp. But it can make it much harder for the tongue to reach the right position.

Losing baby teeth causes a temporary change. This stage lasts a few months, and afterwards the sound usually settles. So do not panic while the teeth are changing.

Permanent differences such as an open bite or a forward jaw need joint work. In this case, our specialist liaises with the orthodontist.

How Does the Assessment Work?

The assessment takes 40 minutes and follows a clear order. We list the steps one by one below.

1. Family interview: we listen to your child's developmental history, dummy use and any ear infections.
2. Sound inventory: the specialist notes each sound one by one as your child says words.
3. Oral motor check: the specialist looks at the tongue tie, palate and bite.
4. Listening check: we see whether your child can tell the correct and incorrect sound apart.
5. Stimulability trial: the specialist models the correct sound, then your child copies it.
6. Report: we give the family written findings and a plan.

Step five largely decides how long therapy will take. If your child copies the model straight away, the process is shorter. For more detail, read our post on the speech and language assessment.

How Does Articulation Therapy Work?

Articulation therapy follows a step-by-step path. Each step builds on the one before.

1. Hearing the difference: the child tells the correct and incorrect sound apart by ear.
2. Single sound: the tip of the tongue moves to the right place, and a clean "s" comes out.
3. Syllable: the sound joins a vowel, for example "sa" and "see".
4. Word: the child practises the target sound at the start, middle and end of words, as in "sun", "missing" and "bus".
5. Sentence: the target sound now goes into short sentences.
6. Conversation: the new sound carries over into everyday talk, which completes the process.

The last step needs the most repetition. A child may speak correctly in the therapy room but slip back into the old habit at home. That is why family involvement directly shapes the result.

How Long Does Therapy Take?

The length depends on the child's age and the type of lisp. For example, 3-6 months is usually enough for an interdental lisp.

With a lateral lisp, the process takes longer. In this case, we plan a programme of 6-12 months. But regular home practice clearly shortens the time.

Sessions usually take place once or twice a week. Each session lasts 40 minutes. Our specialist also reviews progress every 8 sessions.

What Can You Do at Home?

Home practice greatly strengthens the effect of therapy. So we have gathered suggestions that fit easily into your daily routine.

• Practise the target sound together in front of a mirror for 10 minutes a day.
• Model the correct pronunciation, but never correct your child over and over.
• Stop the dummy and bottle completely, because only then can the tongue learn the right position.
• Let your child drink through a straw, and play blowing games.
• Make a short list of words that start with the target sound.
• Turn practice into a game, for example by giving a point for every correct sound.

Short, fun practice gives the best results. A child under pressure may pull away from talking altogether.

6 Common Mistakes Parents Make

Some well-meant habits make a lisp last longer. So watch out for the points below.

1. Saying "say it properly" after every sentence.
2. Finding your child's lisp cute and copying it.
3. Waiting until age 6 because "it will pass anyway".
4. Keeping the dummy until preschool.
5. Starting therapy but skipping the home practice, even though carry-over into everyday speech happens at home.
6. Comparing your child with a sibling or other children.

Instead of these mistakes, choose to be a patient model. This way your child gains both the correct sound and the confidence to speak.

If Your Child Is Teased at School

Teasing from other children quickly lowers a child's wish to talk. So always deal with it together with the school.

Have a short talk with the teacher and briefly explain the therapy process. Once the teacher raises awareness in class, the teasing usually stops.

Teach your child a simple sentence too, for example "I'm working on my sounds." This way your child sees the situation as a process, not something to be ashamed of.

Use the same supportive words at home. Never make your child's speech a joke, and remind siblings of this rule too. A safe environment is therapy's strongest support.

The Process at Çocukla Akademi

At our centre in Beykent, Büyükçekmece (Istanbul), the process for a lisp starts with a speech and language assessment. Our specialist first listens to the family, then maps out which sounds your child can and cannot make.

The plan is shaped around your child. The specialist shares the target sound, session frequency and home programme in the same report. Therapy, family meetings and progress updates can all be in English, and we offer bilingual Turkish-English sessions for bilingual children. For the steps to get started, read our post on how to start speech therapy.

For the scope of our service, see our articulation disorder page. For similar sound difficulties, read our posts on the child who cannot say the R sound and the child who mixes up K and G sounds. If you have a question, write to us via our contact page.

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