If your child says “thun” instead of “sun” or “thoup” for “soup,” you may be hearing a dentalized lisp. This common articulation pattern happens when the tongue pushes too far forward against the teeth while making certain sounds, especially /s/ and /z/.

While dentalized lisps are often part of normal speech development in younger children, persistent lisps after a certain age may benefit from speech therapy. Let’s explore what a dentalized lisp is, what causes it, and how speech-language pathologists (SLPs) help children correct it gently and effectively.

What Is a Dentalized Lisp?

A dentalized lisp occurs when the tongue tip or blade touches or presses too firmly against the upper front teeth while producing the /s/ or /z/ sounds. This causes air to escape in a slightly distorted way, creating a “muffled” or “slushy” sound.

For example:

• “sun” sounds like “thun”

• “zoo” sounds like “thoo”

This differs from an interdental lisp, where the tongue actually sticks out between the teeth. In a dentalized lisp, the tongue stays behind the teeth but still pushes forward enough to disrupt airflow.

Why Dentalized Lisps Happen

There are several reasons a child may develop a dentalized lisp:

• Normal developmental phase: Many young children have slight lisps as they learn precise tongue placement.

• Tongue placement habits: If the tongue naturally rests too far forward, it can affect speech sounds.

• Structural differences: A small gap between front teeth, tongue thrust, or missing teeth may contribute.

• Hearing issues: Children who don’t hear high-frequency sounds clearly may have trouble monitoring their /s/ and /z/ sounds.

• Modeling or imitation: Kids sometimes copy speech patterns from family or peers without realizing it.

Most dentalized lisps are functional rather than physical, meaning they result from learned patterns—not anatomical problems.

How Dentalized Lisps Affect Speech

A dentalized lisp primarily affects the clarity of speech, particularly with the /s/ and /z/ sounds. Some children may be easily understood despite the lisp, while others might feel self-conscious or be teased for how they sound.

In school-age children, lisps can also affect spelling or reading patterns, since hearing and producing clear sound contrasts supports literacy development.

The encouraging news: with practice and professional guidance, most children can eliminate a dentalized lisp completely.

How SLPs Treat Dentalized Lisps

Speech-language pathologists use evidence-based, step-by-step techniques to help children correct tongue placement and airflow for clear /s/ and /z/ sounds. Therapy is typically playful, encouraging, and age-appropriate.

Step 1: Increase Awareness

The SLP helps the child notice where their tongue is during speech. Using mirrors or visual cues, the therapist might say:

“Watch how your tongue stays behind the fence—your teeth are the fence!”

Step 2: Teach Correct Placement

For /s/, the tongue should stay just behind the top teeth, without touching them. Air should flow smoothly through a narrow groove down the center of the tongue. The sides of the tongue touch the top molars to keep the airflow centered.

The SLP may use phrases like:

“Keep your tongue hiding behind your teeth.”
“Let the air sneak out in the middle—like a snake!”

Step 3: Practice in Isolation

Once the child can produce the correct sound on its own, practice begins with single sounds (“ssss”), then short syllables (“see,” “so,” “suh”).

Step 4: Build to Words and Sentences

Gradually, the sound is practiced in real words and phrases, like sun, bus, messy, snakes slide silently.
Each step reinforces consistency and control.

Step 5: Carry Over into Conversation

As accuracy improves, SLPs use games, reading, and storytelling to encourage the correct sound in natural speech. Eventually, the goal is for the child to use clear /s/ and /z/ sounds automatically in all situations.

Helpful Tools and Activities

SLPs often make articulation practice fun and interactive with:

• Mirrors: So the child can see tongue and lip position.

• Straws or feathers: To feel the forward airflow through the center of the tongue.

• Visual mouth models: To show where the tongue should rest.

• Games: Like blowing bubbles, snake-themed activities, or articulation cards that make practice engaging.

At home, parents can support progress by encouraging short daily practice sessions—5 minutes is often enough.

When to Seek Help

Most children naturally refine their /s/ and /z/ sounds by around age 7. If a lisp persists beyond that age—or if it causes frustration or social awareness earlier—it’s a good time to consult an SLP.

Therapy for a dentalized lisp is typically short-term and highly effective. Many children show improvement within weeks or months when therapy and home practice are consistent.

FAQs

Is a dentalized lisp the same as a lisp between the teeth?
No. In a dentalized lisp, the tongue presses against the teeth but doesn’t stick out. In an interdental lisp, it protrudes between the teeth.

Can a lisp go away on its own?
Sometimes. Mild lisps in preschoolers often resolve naturally, but persistent lisps beyond age 7 usually need professional guidance.

Can I help my child at home?
Yes! Model clear /s/ and /z/ sounds, practice short games like “snake sounds,” and use mirrors to make practice visual and fun.