Lisps

What is a lisp?

A lisp is a speech difference where someone has difficulty producing certain sounds, most commonly "s" and "z". It occurs when the tongue moves into an unusual position during speech, changing how these sounds come out.

Lisps are common in young children who are still developing their speech. Most will naturally outgrow a mild lisp without any intervention. This is generally considered a normal part of language development up until around the age of five or six, though monitoring is sensible during this period.

If a lisp continues beyond this age, it may be worth seeking advice from a speech and language therapist. This is particularly relevant if the lisp is affecting how clearly the child can communicate, or if it is causing them frustration or embarrassment. Adults can also have lisps, sometimes persisting from childhood or developing later in life due to changes in dental structure or other factors.

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Types of lisps

There are four main types of lisp, each caused by different tongue positions during speech.

• Interdental lisp: The tongue pushes forward between the front teeth when trying to make an "s" or "z" sound, producing a "th" sound instead. This is often considered the most common type in young children.
• Dentalised lisp: The tongue presses against the back of the front teeth rather than going between them. This creates a slightly muffled quality to the "s" and "z" sounds, though it tends to be less noticeable than an interdental lisp.
• Lateral lisp: Air escapes over the sides of the tongue instead of flowing straight forward, producing a wet or slushy sound quality. Lateral lisps are not part of typical speech development and usually require therapy to correct.
• Palatal lisp: The middle section of the tongue touches the soft palate at the roof of the mouth. The resulting sound can vary between individuals, but it typically distorts the "s" and "z" in distinctive ways that a therapist can identify.

Interdental and dentalised lisps are more commonly seen in young children and often resolve with age or minimal intervention. Lateral and palatal lisps tend to be less common and typically need more structured support from a speech professional.

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When to seek help

If your child is under five and has a mild lisp, there is usually no cause for concern. Many children grow out of it naturally as their speech muscles develop and they learn to position their tongue correctly.

You may want to consider a referral to a speech and language therapist if your child is over five or six and still lisping, if others are struggling to understand them, or if your child is becoming self conscious about their speech. Adults who wish to address a lisp can also benefit from therapy, though the process may take longer and can involve working through established speech patterns alongside any psychological impacts of living with a lisp for many years.

In the UK, NHS speech and language therapy is often accessed through your GP or health visitor. Some areas do allow self referral, though this varies considerably depending on local commissioning arrangements, and GP referral remains the more common route. Waiting times depend on local services. Private speech and language therapists are available if you prefer not to wait or want more frequent sessions. The Royal College of Speech and Language Therapists maintains a directory of registered practitioners on their website, where you can search by location.

What does therapy involve?

Speech and language therapy for lisps typically involves exercises focusing on tongue placement and airflow during speech. A therapist will assess the type of lisp and develop a plan based on individual needs.

Sessions often begin with practising specific sounds in isolation before moving on to words, sentences, and everyday conversation. The therapist will usually give exercises to practise at home between sessions. Progress depends on factors such as the type of lisp, how consistently exercises are practised, and the age of the person receiving therapy.

Many people see improvement within a few months of consistent practice, though results vary between individuals. For children, involving parents and carers in home practice can make a real difference to outcomes.

The Next Step

Now that you have read through the advice above, you might want to put it into practice. Our Speech Concern Checker lets you describe the speech difficulty you or your child is experiencing and get guidance on what it might be. Takes about 2 minutes. Try it now →