Different Types of Lisps: Causes, Sounds, and Speech Therapy Solutions

A lisp is a speech sound disorder affecting the sounds /s/ and /z/. Lisps are caused by the improper direction of airflow during articulation. Lisps are common in childhood, and speech therapy can help. While some children outgrow lisps naturally, others need intervention. Adults can also have persistent lisps from dental or structural abnormalities or as a result of habitual speech patterns.

What Is a Lisp?

A lisp is a speech sound disorder affecting the pronunciation of /s/ and /z/ sounds. Lisps occur due to tongue placement, muscle coordination, or oral structure issues. Lisp can persist into adulthood if untreated.

The 4 Main Types of Lisps

Interdental Lisp (Frontal Lisp)

Frontal lisp is the most common type of lisp. The tongue pushes too far forward, between the front teeth, causing a "th" sound instead of /s/ or /z/. Thumb-sucking or prolonged pacifier use can contribute to this lisp.

Dentalized Lisp

The tongue touches the upper front teeth instead of staying behind them. This lisp results in a slightly muffled or distorted /s/ and /z/ sound.

Lateral Lisp (Slushy Lisp)

Air escapes over the sides of the tongue, creating a "wet" or "mushy" sound. Lateral lisps do not typically disappear on their own and require therapy.

Palatal Lisp

In a palatal lisp, the tongue touches the soft palate (roof of the mouth) instead of the alveolar ridge. This type of lisp is less common and may need targeted intervention.

Other Less Common Types of Lisps

Less common types of lisps include:

• Nasal Lisp or nasal emission, which is technically a resonance disorder. It occurs when the airstream is improperly directed out of the nose.
• Strident Lisp occurs when a whistling sound accompanies sibilant phonemes.
• Addental Lisp is a lisp that occurs due to missing teeth or gaps in the placement of teeth.

What Causes a Lisp?

Common causes of lisp include:

• Tongue placement and muscle coordination issues
• Oral habits like thumb-sucking or prolonged pacifier use
• Structural differences, such as tongue tie or misaligned teeth
• Neurological or motor planning difficulties

Can a Lisp Be Corrected?

Most lisps can be treated effectively with speech therapy, although some may require structural intervention. The factors that impact correction include:

• The child’s age (earlier intervention leads to better results).
• Severity of the lisp and underlying causes.

How Speech Therapy Helps Correct a Lisp

Speech-language pathologists (SLPs) diagnose and treat lisps. See our therapists page for more information. Key therapy techniques for lisps include exercises to focus on tongue placement as well as control and coordination of airflow during articulation.

At-Home Strategies to Support Lisp Correction

You can support your child’s progress with simple, engaging techniques. Techniques parents can use will be provided by the speech therapist and explained in detail. Practicing these techniques is essential to progress. These techniques may include:

• Modeling the correct pronunciation;
• Practicing specific sounds;
• Providing positive reinforcement to increase confidence.

When to Seek Professional Help for a Lisp

Consider speech therapy in the following circumstances:

• If a lisp persists beyond age 5-6;
• If the child struggles to be understood;
• If the lisp affects confidence or social interactions.

A speech-language evaluation can determine the best approach.

Supporting Your Child’s Speech Journey

Parents should know that every child’s progress looks different. Early intervention and patience with speech development are important.

Verse Therapy’s expert SLPs can help create a personalized therapy plan.

Start Your Speech Journey!