Understanding Lisps: The 4 Main Types Explained
1. Interdental Lisp
An interdental lisp occurs when the tongue protrudes between the front teeth during speech.
- How it sounds: “s” and “z” sound like “th”
- Example: “sun” → “thun”
This is the most common lisp in young children and is often part of early speech development.
2. Dentalised Lisp
In a dentalised lisp, the tongue pushes against the front teeth but does not protrude.
- How it sounds: “s” and “z” may sound muffled or dull
- Example: “zoo” → soft, unclear “zoo”
This lisp can be subtle but still impacts speech clarity.
3. Lateral Lisp
A lateral lisp occurs when air escapes over the sides of the tongue instead of flowing forward.
- How it sounds: “s,” “z,” “sh,” and “ch” may sound slushy or wet
- Example: “shoe” → slushy “shoo”
This is not developmentally typical and always requires speech therapy.
4. Palatal Lisp
A palatal lisp happens when the tongue contacts the soft palate too far back.
- How it sounds: Distorted “s” and “z” sounds
- This type is rare and often linked to learned speech patterns.
Understanding the types of lisp allows our speech pathologists to design precise and effective lisp treatment plans.
Comparison of Lisp Types
| Lisp Type | Sound Error | Tongue Position | Developmental Norm |
|---|---|---|---|
| Interdental lisp | “s/z” → “th” | Tongue between teeth | Common under 4½ |
| Dentalised lisp | Muffled “s/z” | Tongue against teeth | May persist |
| Lateral lisp | Slushy airflow | Air escapes sides | Not typical |
| Palatal lisp | Distorted sounds | Tongue too far back | Not typical |
When Should You Seek Help for a Lisp?
- Interdental lisp: Common in toddlers and preschoolers. If it continues beyond 4½-5 years, therapy is recommended.
- Dentalised lisp: May not resolve on its own. Speech therapy is advised once the child can follow instructions (around age 4).
- Lateral lisp: Not developmentally appropriate at any age. Therapy should begin as soon as identified.
- Palatal lisp: Requires assessment regardless of age.
Adults with persistent lisps can benefit significantly from lisp speech therapy, even if the speech pattern has been present for years.
How Long Does Lisp Speech Therapy Take?
The duration of lisp speech therapy varies depending on age, lisp type, consistency, and practice. Regular attendance and home practice are key to achieving lasting results.
How Long Does Lisp Speech Therapy Take?
We provide:
Our Lisp Speech Therapy Treatment Process
We assess:
- Lisp type
- Oral motor patterns
- Speech sound awareness
- Impact on confidence and communication
Clients learn:
- How the target sound should feel and sound
- Differences between correct and incorrect production
We teach precise tongue placement using:
- Visual cues
- Tactile feedback
- Mirrors
- Modelling
Sounds are practised through:
- Isolated sounds
- Syllables
- Words and sentences
We support the transfer of correct speech into:
- Conversations
- School or work settings
- Everyday communication
Strategies ensure long-term success and prevent relapse.
Therapy is available in-clinic or via telehealth speech pathology, making support accessible wherever you are.
Ready to Start Lisp Speech Therapy?
Lisp Speech Therapy FAQs
Will my child grow out of their lisp?
Some children may naturally outgrow an interdental lisp by age 4½. However, lateral and palatal lisps do not resolve on their own. If a lisp persists beyond expected age ranges, Speech therapy is recommended to address the lisp early and reduce the risk of it persisting into long-term speech patterns.
Can speech therapy fix a lisp?
Yes. Speech therapy is highly effective for treating all types of lisps. With targeted placement training and structured practice, most clients achieve clear, accurate speech through professional lisp treatment.
At what age is a lisp a problem?
Lisps are considered a concern when they persist beyond developmental norms. Interdental lisps beyond age 5, or any lateral lisp at any age, should be assessed by a speech pathologist.
What exercises help with a lisp?
Effective exercises include tongue placement drills, sound contrast activities, and structured repetition. These are most successful when guided by a speech pathologist as part of a personalised lisp speech therapy plan.
Is a lateral lisp more difficult to treat?
A lateral lisp can take longer to treat because it involves airflow redirection rather than simple tongue placement. However, with consistent therapy, progress is very achievable using evidence-based lisp treatment approaches.
Can adults still improve their lisp with therapy?
Absolutely. Adults can make significant progress with lisp speech therapy, even if the pattern has been present for many years. A lisp often becomes a deeply ingrained habit, but with structured practice, awareness training, and consistent guidance from a speech pathologist, many adults learn correct tongue placement and airflow and achieve clearer speech. Improvement might take longer than in children because adults may need to override long‑established speech patterns, but therapy is effective and empowering at any age.
What happens if a lisp is left untreated?
If a lisp persists without intervention, it can continue into adolescence and adulthood, potentially affecting speech clarity, confidence, and social interactions. While some mild lisps in young children resolve naturally, others can become more entrenched over time. Persistent lisps may contribute to misunderstandings in communication, frustration, and reduced self‑esteem, especially in situations like school presentations, job interviews, or everyday conversations. Early assessment and tailored lisp treatment can help prevent long‑term impacts.
