Articulation
S Sound Speech Therapy: How to Fix a Lisp
Evidence-based treatment strategies for frontal and lateral lisps, plus home practice activities
January 11, 2026•15 min read
Evidence-based treatment strategies for frontal and lateral lisps, plus home practice activities
"My child has a lisp—will they grow out of it?" It's one of the most common questions SLPs hear from parents. And the answer depends entirely on what type of lisp it is and how old the child is.
The /s/ sound appears in roughly 10% of all English words—think "sun," "bus," "smile," "yesterday." When it's distorted, it's noticeable. Kids notice. Parents notice. Teachers notice. And often, the child notices too, which can affect their confidence when speaking up in class or talking to friends.
Here's what parents and SLPs should know: lisps are among the most treatable speech sound disorders. With the right techniques and consistent practice, most children achieve clear /s/ production—and often faster than families expect. This guide breaks down the different types of lisps, when to intervene, and what actually works in treatment.
Not all lisps are the same. Identifying the specific type is crucial for effective treatment:
The most common type. The tongue protrudes between the front teeth during /s/ and /z/ production, making these sounds come out like "th." A child might say "thun" for "sun" or "thoup" for "soup."
Developmental note: Frontal lisps are considered developmental up to age 4-5. Many children naturally outgrow them without intervention.
Air escapes over the sides of the tongue instead of down the center, creating a "slushy" or wet sound. This is sometimes described as a "Sylvester the Cat" sound.
Important: Lateral lisps are NOT developmental and typically require speech therapy at any age. They rarely resolve without intervention.
The tongue pushes against the front teeth (but not between them), producing a slightly muffled /s/. This is less noticeable than other lisp types but can still affect speech clarity.
The tongue contacts the soft palate (roof of the mouth) during /s/ production, creating a sound closer to "sh" or a muffled quality. Less common than frontal or lateral lisps.
Lisps typically result from incorrect tongue placement, but several factors can contribute:
For most children with lisps, there's no single identifiable cause—they simply need to learn the correct motor pattern for /s/ production through targeted practice.
According to developmental norms, /s/ is typically acquired earlier than many other sounds:
Research by Smit et al. (1990) found that 90% of children produce /s/ correctly by age 5;0 in conversation. However, if your child has a lateral lisp, don't wait—these require therapy regardless of age and won't resolve on their own.
Understanding correct placement helps guide therapy:
The /s/ sound is voiceless—the vocal cords don't vibrate. The /z/ sound uses the same tongue position but adds voicing. Once a child masters /s/, /z/ often follows quickly.
The systematic approach progresses through levels: isolation → syllables → words → phrases → sentences → conversation. At each level, the child must achieve a high accuracy rate (typically 80-90%) before advancing.
Best for: Children with frontal lisps who can produce /s/ correctly with cues or in at least one context.
These techniques provide explicit instruction on tongue positioning:
Have the child smile, put their tongue tip behind their top teeth, and keep the sides of their tongue up like "butterfly wings." Then blow air through the middle.
Start with a /t/ sound and hold it, slowly releasing the air. The /t/ position naturally places the tongue in the right spot for /s/.
Use a thin straw placed at the center of the lips while producing /s/. This provides tactile feedback about airflow direction and helps establish central airflow for lateral lisp treatment.
Lateral lisps require specific techniques to redirect airflow from the sides to the center of the tongue:
Research by Bacsfalvi and Bernhardt (2011) found that visual biofeedback tools, including ultrasound imaging, can be particularly effective for lateral lisp treatment by helping children visualize tongue positioning.
If the child also has a tongue thrust swallowing pattern, this may need to be addressed alongside or before articulation therapy. Orofacial myofunctional therapy (OMT) can help establish correct tongue resting posture and swallowing patterns, which supports lasting /s/ improvement.
Consistent practice between therapy sessions accelerates progress. Here are effective activities for home:
Practice 10-15 words at your child's current level. Focus on one position at a time:
Practice in front of a mirror so your child can see their tongue position. For /s/, they should see their tongue staying behind their teeth—not poking through. Make it a game: "Can you keep your tongue hiding?"
Play "snake" by having your child produce a long /s/ sound ("sssssss") while "slithering" a toy snake across the table. See who can make the longest, clearest snake sound.
Play I Spy focusing only on objects that start or end with /s/: "I spy something that's a ssssock!" This encourages natural practice in a fun context.
One challenge parents face is knowing whether their child's /s/ sounds correct. AI-powered apps like LumaSpeech can provide real-time feedback on /s/ productions, ensuring home practice reinforces correct patterns. This is especially valuable for detecting subtle errors that untrained ears might miss.
Consider consulting a speech-language pathologist if:
An SLP can conduct a comprehensive evaluation to determine the type of lisp, identify any contributing factors, and create a targeted treatment plan.
Treatment duration varies based on several factors:
The key predictor of success isn't the severity of the lisp—it's the consistency of practice. Studies show that home practice frequency is strongly correlated with treatment outcomes.
Whether your child has a frontal lisp, lateral lisp, or other /s/ distortion, improvement is absolutely achievable. With evidence-based therapy techniques and consistent home practice, most children can develop clear, confident /s/ production.
Tools like LumaSpeech can support the journey by providing AI-powered feedback during home practice, helping ensure that practice time builds correct patterns and accelerates progress toward clear speech.