Understanding the Four Types of Lisps and How SLPs Help Correct Them

A child’s speech journey is full of adorable moments — but when a lisp persists past the toddler years, parents often start to wonder if it’s time for help. Lisps are one of the most common speech patterns SLPs see, and the good news is that they’re highly treatable with the right approach.

In this article, we’ll explore the four main types of lisps, what causes them, and how speech-language pathologists (SLPs) help children learn to produce crisp, clear sounds.

What Is a Lisp?

A lisp is a speech pattern where a person has difficulty producing certain sibilant sounds, such as /s/ and /z/. These sounds might come out distorted, slushy, or muffled.

Most lisps involve the tongue pushing too far forward or sideways during speech. Because /s/ and /z/ are made by directing air through a narrow space between the tongue and teeth, even a small change in tongue placement can change the sound completely.

While some lisps are normal in young children learning to talk, persistent lisps after age 7 or 8 may need professional support.

The Four Main Types of Lisps

Not all lisps sound the same. In fact, SLPs classify them into four main types based on tongue placement and airflow direction.

1. Frontal Lisp (Interdental Lisp)

This is the most common type. The tongue pushes forward between the front teeth when making /s/ and /z/ sounds, causing them to sound like “th.”

Example:

• “Sun” becomes “thun.”

• “Busy” sounds like “bithy.”

Frontal lisps are typical in young children up to around age 5, but beyond that age, they often require therapy.

How SLPs Help:
Therapy focuses on teaching correct tongue placement — behind the teeth, not between them. SLPs may use mirrors, tongue depressors, or tactile cues to help children feel where the tongue should go. Fun articulation games make practice engaging and rewarding.

2. Lateral Lisp

A lateral lisp happens when air escapes from the sides of the tongue instead of the center, giving the /s/ and /z/ sounds a “slushy” or “wet” quality.

Example:
The /s/ in “sun” might sound like a mix between /sh/ and /l/.

This type of lisp isn’t considered a normal developmental stage and usually doesn’t go away without therapy.

How SLPs Help:
SLPs teach the child how to keep the sides of the tongue sealed against the top teeth and direct airflow down the middle. Practice often starts with /t/ sounds and gradually moves toward clear /s/ and /z/ production.

3. Palatal Lisp

A palatal lisp occurs when the tongue touches or comes too close to the soft palate (the roof of the mouth) during /s/ or /z/ sounds. The result can sound somewhat like a “sh” sound.

Example:
“See” might sound like “shee.”

Palatal lisps are less common but still treatable.

How SLPs Help:
The SLP helps the child bring the tongue tip forward, away from the palate, and teaches correct tongue-to-teeth positioning. Visual feedback and structured drills help retrain the correct movement pattern.

4. Dental Lisp (Dentalized Lisp)

In a dental lisp, the tongue pushes against the back of the front teeth rather than between them. The sound can still come out muffled or distorted, but it’s subtler than a frontal lisp.

Example:
“Sun” might sound dull, almost like “thun,” but with less obvious tongue protrusion.

How SLPs Help:
Therapy emphasizes gentle retraction of the tongue so it rests just behind the teeth. Children practice holding this position while producing clear /s/ and /z/ sounds in words and sentences.

Common Causes of Lisps

Lisps can occur for a variety of reasons, including:

• Oral habits such as thumb sucking or prolonged pacifier use

• Tongue thrust (pushing the tongue forward during swallowing and speech)

• Dental or jaw alignment issues

• Hearing difficulties, making it hard to monitor sound accuracy

• Learned speech patterns that persist past the typical age

An SLP’s assessment helps determine whether the lisp is part of normal development or linked to another underlying cause.

How Speech Therapy Corrects a Lisp

Speech therapy for lisps focuses on retraining tongue placement and airflow patterns through consistent, fun, and structured practice. Here’s what therapy typically includes:

1. Awareness Training

The child learns how to feel the difference between the “old” and “new” tongue positions. Mirrors and videos can help them see what’s happening.

2. Sound Production Practice

The SLP introduces the target sound in isolation (just the /s/ sound), then gradually moves to syllables, words, phrases, and full sentences.

3. Generalization Activities

Once the sound is mastered, therapy focuses on using it naturally in conversation, reading, and storytelling.

4. Home Practice

Parents play an important role! Short, daily practice at home helps the new speech pattern become automatic. Many SLPs provide games, picture cards, or online materials to make home practice easy.

When to Seek Help

Most children outgrow mild frontal lisps by age 5. If a lisp continues beyond kindergarten, it’s a good idea to schedule an evaluation. An SLP can quickly determine whether your child’s sound errors are developmental or require therapy.

For older children, teens, and adults, therapy is still effective. Progress may take time, but with motivation and consistent practice, clear speech is absolutely achievable.

FAQs

Can lisps be corrected at any age?
Yes! While early intervention helps, children, teens, and adults can all improve their speech through targeted therapy.

Do braces cause or fix lisps?
Braces can temporarily affect tongue space, but they don’t usually cause lisps long-term. Once orthodontic work is complete, an SLP can help fine-tune sound placement if needed.

How long does it take to fix a lisp?
It depends on the type and severity. Many children show improvement within a few months of consistent practice and parent support.

Final Thoughts

A lisp doesn’t define a child’s ability to communicate — it’s simply a pattern that can be changed with guidance and practice. With the help of a skilled SLP, children learn to speak with clarity, confidence, and pride in their voice.