Lisps in children: what can help

Hearing your child say ‘thun’ for ‘sun’ can bring a quick run of questions. Is it normal, will it pass, and does it need treatment? The charity Speech and Language UK says there is no known cause for a lisp, and many lisps fade by themselves.

What is a lisp?

A lisp is a difference in how the ‘s’ sound is made. Speech and Language UK describes it as the tongue not sitting in its usual position, so ‘s’ can sound slushy, wet, hissy or more like ‘th’. You can usually tell the child is trying to say ‘s’.

There are four main types. Three of them are in the table.

Type	What the tongue does	What you hear
Interdental	Pushes forward between the front teeth	‘Sock’ sounds like ‘thock’
Dentalised	Presses against the front teeth	A muffled ‘s’ or ‘z’
Lateral	Lets air escape out of the sides	A slushy, wet sound

A fourth type, palatal, where the middle of the tongue touches the roof of the mouth, is the least common.

The type matters. According to Whittington Health NHS Trust, an interdental lisp is common in children until about the age of 5 and is part of typical speech development. A lateral lisp is different: the trust notes it is not part of typical development, and a child may benefit from support from a speech and language therapist.

Some families want help so their child sounds clearer. Speech and Language UK also notes that others see a lisp as simply a different way of talking. They accept it as part of what makes their child who they are.

Why do lisps happen?

For most children, Speech and Language UK says, they have simply learned to say ‘s’ a different way and it has become a habit. Children are more likely to have a lisp if a close family member has one. Beyond that, parents often ask about three other things that can affect how speech develops. The sources do not firmly link any of them to lisps, and they differ on dummies.

Dummies and bottles

Speech and Language UK lists long-term dummy or bottle use among the traditional explanations, with no strong evidence behind it. The Royal College of Speech and Language Therapists (RCSLT) says a dummy used to settle a child does not affect speech development. It adds that long spells of use through the day, while a child is starting to talk, can interfere with speech sound development.

Tongue-tie

Tongue-tie is where the skin under the tongue is shorter or tighter than usual. The NHS notes it may not cause any problems, though it can make the tongue harder to move. The NHS says that if it does cause problems, such as difficulty feeding in babies, treatment is available. The RCSLT says research has not shown that tongue-tie affects how speech develops, so speech is not a reason to have it cut, at any age. If you think your child has tongue-tie, the NHS advises speaking to a midwife, health visitor or GP.

Hearing

Good hearing helps speech sounds develop, according to the RCSLT. Children can have periods of reduced hearing from infections or blockages in the ears, such as glue ear. The NHS adds that glue ear that lasts a long time can affect a child’s speech development. It lists being difficult to understand and asking people to repeat themselves among the signs of a hearing problem, and advises seeing a GP.

Will my child grow out of it?

Often, yes. Speech and Language UK says lisps often disappear in time without therapy, usually by the age of 4 or 5. Whittington Health NHS Trust agrees that most children grow out of them when they are ready.

The RCSLT adds a note of caution for children whose speech is much harder to understand than that of other children their age, which it calls a speech sound disorder. It gives a lisp as one example. For these children, it says only a small number catch up without help, and children of school age are unlikely to improve without therapy. A lateral lisp, or one that is still there after about age 5, is worth having looked at rather than waiting.

What can help at home?

Speech and Language UK and Whittington Health NHS Trust suggest similar steps:

• Focus on what your child says rather than how they say it, and be positive and accepting of how they sound.
• Say the word back clearly. If they say ‘I want the blue thock’, you can say ‘You want the blue sock’. You do not need to ask them to say it again, because the RCSLT says asking a child to repeat can lead them to avoid talking.
• If your child is willing, use a mirror to show that the tongue stays behind the teeth for ‘s’.
• Pick four or five simple ‘s’ words you use every day, such as sock, sandwich or soap, and emphasise the sound.
• Play I Spy with things that start with ‘s’ and ‘th’.
• If your child uses a dummy or bottle, try to reduce it.
• Avoid putting too much pressure on them if they are not ready.

Check before you buy anything. The RCSLT says some tongue and mouth exercises, chewing tools and speech apps sold online claim to help children with speech sound difficulties. It says there is no research that these exercises work, that some can be harmful, and that most apps will not help. It advises talking to a speech and language therapist first. If you are waiting for therapy, it suggests asking the therapist what you can do, and says this could be as simple as reading or listening to books together.

When does speech and language therapy help?

According to Speech and Language UK, therapy may help if a lisp makes your child hard to understand, or if it is an unusual type. It helps if the child wants to work on it and can focus on the activities. Its advice if you are concerned is to contact a speech and language therapist, who can assess what kind of lisp it is.

The RCSLT notes that if parents and carers are very concerned, they can often contact their local NHS speech and language therapy service directly. Some services only accept referrals from a health visitor or school. It adds that some children find a speech sound difficulty affects their wellbeing and mental health, and that referral can help. Therapy usually has a waiting list, so ask the therapist what you can do at home in the meantime. At a first assessment the therapist usually asks about your child’s development and, for younger children, uses play and pictures to encourage them to talk.

Do teeth and bite play a part?

Possibly, in some people, and the evidence is mixed. Speech and Language UK describes the position or movement of the jaw, teeth and tongue as traditionally linked to lisps, with no strong evidence.

Dental research looks at it more closely. A 2025 scoping review of 12 studies of children with baby teeth or a mix of baby and adult teeth found that all of them reported a link between malocclusion and speech sound disorders. The studies looked at speech sound problems in general, not only lisps. Malocclusion means teeth that are crowded or do not fit together well. The effect was most notable for anterior open bite, where there is a gap between the upper and lower front teeth when the back teeth bite together. The authors say the exact cause and effect are still unclear.

A 2023 review written for dental professionals looks at how development, jaw problems and jaw surgery affect speech. It says that whether jaw surgery for a severe bite problem improves speech is still being studied. The reviews cited here do not show that straightening teeth on its own corrects a lisp. The 2023 review adds that for some growing children orthodontic treatment and speech therapy may be combined. It also says that dental teams who understand speech problems can screen for them and guide referral.

Orthodontic appliances can also affect speech. A 2023 systematic review of seven studies found that clear aligners can affect speech, with lisping among the errors reported, in a similar way to fixed braces. The difficulty was temporary: most people recovered within 7 to 14 days and a few took 30 to 60 days. The review rated the evidence as low quality.

So a dentist can look at whether the way your teeth fit together may be involved. Whether straightening would change a lisp is not settled.

When to get a lisp checked

What we would do

We do not offer speech and language therapy, which is provided by speech and language therapists. What a dental visit can do is look at the teeth and mouth.

A new patient exam is a full check of your teeth, gums and mouth, with small X-rays where needed, and usually takes 15 to 20 minutes. Tell your dentist about the lisp. For younger patients, our children’s dentistry page explains how we look after children from their first visit. Our guide to oral health and your children is a general read for parents.

If your dentist thinks the way the teeth fit together needs a closer look, they can explain whether a teeth straightening consultation makes sense. We cannot promise that straightening would change a lisp, and for the lisp itself the place to start is speech and language therapy.

If you would like a dentist to look at your teeth and bite, book an appointment and mention the lisp.

Want us to take a look?

Book an appointment at whichever of our five practices suits you. We will check what is going on and talk you through your options.

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