What Is a Lateral Lisp? Signs, Causes, and Strategies That May Help
Have you noticed that your child’s “S” sound sounds slushy, wet, or as though air is escaping from the sides of their mouth? This may be a sign of a lateral lisp, a type of speech sound error that can affect how clearly a child produces certain sounds.
A lateral lisp occurs when air escapes over one or both sides of the tongue instead of flowing forward through the centre of the mouth. It most commonly affects the /s/ and /z/ sounds, giving them a distinctive slushy or wet quality.
For parents looking for speech therapy in Vaughan, Ontario, understanding what a lateral lisp sounds like and how it may be addressed can be a helpful first step toward supporting their child’s speech development.
At Kurliand Speech Clinic, we support children and families with speech sound development and communication. In this article, we explain what a lateral lisp is, explore strategies that may help, and discuss when to consider an assessment with a speech-language pathologist.
What Does a Lateral Lisp Sound Like?
A lateral lisp changes the way certain speech sounds are produced. To understand the difference, it helps to look at how airflow moves during typical /s/ production.
When producing a clear /s/ sound, air travels forward through a narrow groove along the middle of the tongue. With a lateral lisp, air escapes over the sides of the tongue instead. This change in airflow creates the characteristic slushy or wet sound (Munnich et al., 2023).
Typical /s/ production:
The tongue creates a narrow channel for air.
Air travels forward through the centre of the mouth.
The resulting sound is crisp and clear.
Lateral lisp:
Air escapes over one or both sides of the tongue.
The airflow is not directed forward through the centre in the typical way.
The /s/ or /z/ sound may sound slushy or distorted.
A lateral lisp is different from a frontal lisp, in which the tongue moves too far forward and may protrude between the front teeth during sounds such as /s/ and /z/.
Understanding the type of speech sound error is important because different speech patterns may require different therapy approaches.
What Causes a Lateral Lisp?
A lateral lisp involves a difference in how the tongue is positioned and how airflow is directed during speech. A child may develop a habitual tongue placement pattern that makes it difficult to produce a clear /s/ or /z/.
The exact factors contributing to a lateral lisp can vary from child to child. An assessment with a speech-language pathologist (SLP) can help identify the nature of the speech sound error and determine which treatment approach may be appropriate.
Simply asking a child to “say your S again” may not be enough to change an established speech pattern. Some children need support to understand where their tongue should be positioned and how to direct airflow through the centre of the mouth.
How Can You Help a Child With a Lateral Lisp?
Parents often wonder whether they can help their child practise speech sounds at home. There are strategies that may help children become more aware of tongue placement and airflow.
However, not every strategy is appropriate for every child, and practising an incorrect sound pattern repeatedly may make it harder to establish a new one.
The following techniques are examples of approaches that may be explored with guidance from a speech-language professional.
1. Explore the “Butterfly Position”
The Butterfly Position is a technique described by speech-language pathologist Pam Marshalla. It uses the image of a butterfly’s wings to help explain tongue placement.
Imagine the sides of the tongue as butterfly wings. The sides lift toward the upper side teeth while the middle of the tongue remains slightly lower, creating a groove that can help direct airflow forward.
When exploring this position, a child may be encouraged to:
Open their mouth slightly.
Lift the sides of their tongue toward their upper side teeth.
Keep the middle of the tongue slightly lower to create a central groove.
Notice the tongue position in a mirror, if helpful.
Work toward directing airflow forward through the centre of the mouth.
The goal is to help the child become aware of tongue placement before attempting to produce a clear /s/ sound. A speech-language pathologist can determine whether this technique is suitable and help the child learn the movement accurately.
2. Use a Mirror for Visual Feedback
Some children benefit from seeing their mouth movements while practising speech sounds. A mirror may help them notice their tongue and jaw position and become more aware of how they are producing a sound.
Visual feedback can be one component of speech sound therapy. Research has also explored specialised visual feedback tools, such as ultrasound, to help individuals learn more accurate tongue movements (Cleland et al., 2015).
However, a regular mirror does not show exactly where air is travelling inside the mouth. It is best used as a supplementary tool rather than a way to diagnose or correct a lateral lisp independently.
3. Focus on Airflow Awareness
Children with a lateral lisp may not realise that air is escaping over the sides of their tongue. Helping them understand the difference between forward and sideways airflow may be useful when incorporated into an appropriate therapy approach.
A clinician may use visual or tactile cues to help a child understand the intended direction of airflow. Some approaches also explore tools, such as a straw, to provide additional feedback.
It is important to remember that blowing through a straw or practising oral movements alone does not correct a lateral lisp. The child ultimately needs to learn how to coordinate tongue placement and airflow during speech.
For this reason, it is best to consult a speech-language pathologist before beginning structured practice, particularly if your child consistently produces a slushy /s/ or /z/.
4. Practise Speech Sounds at the Right Level
Once a child can produce a target sound accurately, speech therapy may progress gradually from individual sounds to syllables, words, sentences, and everyday conversation.
For example, practice may begin with a clear /s/ sound before moving to words such as “sun,” “sock,” and “bus.” As the child becomes more consistent, practice can expand to longer phrases and spontaneous speech.
The appropriate starting point depends on the child's current speech skills. Some children need help establishing the sound first, while others are ready to practise using it in words or conversation.
Short, positive practice opportunities are generally preferable to repeatedly correcting a child throughout the day. Encouragement can help keep speech practice comfortable and motivating.
When Should You Seek Speech Therapy for a Lateral Lisp?
Consider contacting a speech-language pathologist if your child:
Consistently produces a slushy, wet, or distorted /s/ or /z/.
Has difficulty producing these sounds clearly, even with reminders.
Continues to use the same speech pattern despite practice.
Is becoming frustrated when trying to say certain words.
Has speech sound difficulties that affect their overall speech clarity.
There is no need to wait until a child is older if you have concerns about their speech. An SLP can assess your child’s speech sound production, consider their age and overall communication development, and determine whether intervention is appropriate.
Not every speech sound difference requires therapy, and the best approach depends on the individual child. An assessment can help clarify whether a lateral lisp is present and identify suitable next steps.
Speech Therapy for Lateral Lisps in Vaughan, Ontario
If you are concerned about your child’s /s/ or /z/ sounds, working with a speech-language professional can help you understand their needs and explore appropriate treatment options.
Kurliand Speech Clinic provides speech and language services in Vaughan, Ontario, including in-clinic and in-home services in Vaughan and surrounding communities, as well as virtual services across Ontario.
Our team supports children with speech sound difficulties, articulation, language development, and other communication needs. Depending on the child’s needs, services may be provided by a registered speech-language pathologist or by a Communicative Disorders Assistant (CDA) or Speech-Language Pathology Assistant (SLPA) working under SLP supervision.
If you have noticed a lateral lisp or are concerned about your child’s speech clarity, we invite you to contact Kurliand Speech Clinic to learn more about our services and whether a speech and language assessment may be appropriate.
Looking for speech therapy in Vaughan? Visit kurliandspeechclinic.ca to learn more about our services and how we can support your child’s communication development.
References
Cleland, J., Scobbie, J. M., & Wrench, A. A. (2015). Using ultrasound visual biofeedback to
treat persistent primary speech sound disorders. Clinical Linguistics & Phonetics, 29(8–
10), 575–597. https://doi.org/10.3109/02699206.2015.1016188
Curtis, S., & Mason, K. (2026, September). Getting it straight: A field guide to lateral lisps.
The Informed SLP. https://www.theinformedslp.com/review/Getting-it-Straight-A-Field-
Guide-to-Fixing-Lateral-Lisps
Marshalla, P. (2009, April 15). Stimulating the Butterfly Position. Marshalla Speech &
Munnich, P., Dederichs, S., Klein, P., & Bruno Figura, C. (2023). Speech intelligibility: Lateral
lisp detection for real-time monitoring. Current Directions in Biomedical Engineering,
9(1), 283–286. https://doi.org/10.1515/cdbme-2023-1071
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