Lateral Lisp: Why S Sounds “Slushy” and How It’s Treated
A lateral lisp is when air escapes over the sides of the tongue during S and Z, giving a wet, “slushy” sound. Unlike a frontal lisp, a lateral lisp is not part of typical speech development at any age and rarely resolves on its own — so it’s worth having a speech-language pathologist assess it whenever you hear one.
What a lateral lisp is
A lateral lisp happens when the air for S and Z escapes over the sides of the tongue instead of being channeled straight down the middle. That side-airflow is what creates the characteristic wet, “slushy” sound — some parents describe it as sounding like there is too much saliva around the S.1
It affects the same sounds as a frontal lisp (S and Z), but the mechanism — and the sound — are different. Where a frontal lisp is the tongue too far forward, a lateral lisp is about which direction the air goes.2
Why a lateral lisp is different — and worth checking
This is the key difference from a frontal lisp: a lateral lisp is not part of typical speech development at any age. Children do not usually pass through it as a normal stage, and it rarely resolves on its own.1
Don’t wait it out
Because a lateral lisp isn’t developmental and doesn’t typically self-correct, “let’s see if they grow out of it” is not the right approach. If you hear a wet, slushy S at any age, it’s worth a speech-language evaluation.
How a lateral lisp is treated
Therapy retrains the airstream to flow down the center of the tongue. A speech-language pathologist typically starts from a sound or position that already channels air down the middle, gives clear feedback on the airflow, and shapes a clean S from there — then builds it into words, sentences, and conversation.1,7
A lateral lisp can take more focused practice than a frontal one, but it is very treatable. Progress is usually faster with a therapist guiding the airflow, since the correction is hard to feel without feedback.7
Free Lisp Assessment
Check whether your child’s S sounds like a lateral (slushy) lisp.
When to see a speech-language pathologist
When to get an evaluation
Any wet, “slushy” S is worth a speech-language evaluation, at any age — a lateral lisp is not developmental and does not typically resolve on its own. Earlier assessment means earlier, easier correction.
A certified speech-language pathologist can confirm it’s a lateral lisp and target it directly, in person or by teletherapy, which is effective for many children.6,5
You often do not need a referral — your local school district can evaluate a child age 3 and older, and you can find a certified SLP through ASHA’s directory.8,2
Frequently asked questions
What is a lateral lisp?＋
A lateral lisp is when air escapes over the sides of the tongue during S and Z instead of flowing down the middle. That side-airflow gives S a wet, “slushy” quality — sometimes described as sounding like there’s too much saliva. It affects the same sounds as a frontal lisp but sounds quite different.
Is a lateral lisp normal?＋
No. Unlike a mild frontal lisp, a lateral lisp is not part of typical speech development at any age. It does not reflect a stage children pass through, and it rarely goes away on its own — so it is worth having assessed whenever you notice it, rather than waiting for it to resolve.
What’s the difference between a lateral and a frontal lisp?＋
A frontal (interdental) lisp pushes the tongue between the front teeth, making S sound like “th” — common and often developmental. A lateral lisp keeps air spilling over the sides of the tongue, making S sound wet and “slushy.” The frontal one is usually the tongue too far forward; the lateral one is airflow going out the sides.
How is a lateral lisp treated?＋
Treatment retrains the airstream to flow straight down the center of the tongue rather than over the sides. A speech-language pathologist uses cues and feedback — often starting from sounds that already channel air down the middle — to shape a clean S, then builds it into words and sentences. It can take focused practice, but it is very treatable.
When should I see a speech therapist about a lateral lisp?＋
Any time you hear a wet, “slushy” S, it is worth a speech-language evaluation — regardless of your child’s age. Because a lateral lisp is not developmental and does not typically self-correct, earlier assessment and therapy are better than waiting.
Put this into practice today
Try the free free lisp assessment, or start daily AI speech practice — every child takes one SpeechStep at a time.
References
8 sources from authoritative bodies. Last reviewed July 2026.
- 1.ASHASpeech Sound Disorders: Articulation and Phonology — Practice Portal page.
- 2.ASHASpeech Sound Disorders — Consumer page.
- 3.ASHATypical Speech and Language Development — Consumer page.
- 4.ASHACommunication Milestones: Age Ranges (Birth to 5) — Developmental milestones.
- 5.NIDCDSpeech and Language Developmental Milestones — Fact sheet.
- 6.ASHATelepractice — Practice Portal page.
- 7.ASHAScope of Practice in Speech-Language Pathology — Policy document.
- 8.ASHAASHA ProFind — Find a Certified SLP — Clinician directory.