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  • Writer's pictureStephanie Jeret

How to Fix a Lisp

Updated: Mar 10

Speak with Stephanie speech therapist helping pediatric client correct a lisp in Wilmette, Illinois

A lisp is a very common articulation disorder (which can also be classified as an oromyofunctional disorder) and occurs in approximately 23% of individuals worldwide. Lisping impacts both children and adults. Often, many adults carry unresolved lisps from childhood that were never addressed or remediated properly.

While most people think of lisping as occurring on the /s/ sound, lisping actually occurs on a group of sounds called sibilants. These sounds include /s/, /z/, /sh/, /zh/ (like measure), /ch/, and /j/.

In this blog post, we will discuss:

Different Types of Lisps

It is important to identify the specific type of lisp you or your child exhibit to effectively address it. This may assist in understanding the underlying issue and will determine the appropriate treatment strategies.

Interdental Lisp: This is the most common and well-known type of lisp, characterized by the tongue protruding through the teeth and the lowering of the jaw. This change in tongue and jaw position impacts the sound produced, often resulting in reduced intelligibility.

Someone with an interdental lisp may produce “thun” for the word sun.  

Lateral Lisp: Air escapes over the sides of the tongue instead of down the center or midline, producing wet or slushy sounds due to the mixing of air and saliva as the person speaks. 

Someone with a lateral lisp may pronounce the word sick as "shik."

Dental Lisp: In this type of lisp, the tongue makes contact with the front teeth but does not protrude through the mouth, leading to a distorted and muffled sound.

Palatal Lisp: Less common, this lisp occurs when the mid-section of the tongue makes contact with the hard or soft palate.  The sound produced often sounds somewhat slushy and muffled.

Mixed Lisp: Some individuals may exhibit a combination of the above lisps, resulting in a more complex lisp pattern.

Causes of a Lisp

Speak with Stephanie speech therapist helping adult client correct a lisp in Skokie, Illinois

A lisp is a functional speech disorder which means the cause cannot always be determined.  However, some known causes for lisps include:

  • Incorrect Practice: Children acquire sounds through imitation and practice from the adults around them. If the adults they are imitating have a lisp, it is possible the child will develop a lisp.

  • Developmental: High frequency hearing loss can impact the development of speech production. Some can develop a lisp for this reason.

  • Anatomical: In some cases a lisp can be caused by structural factors.  Irregularities in the soft palate, tongue, teeth, or positioning of the teeth can all contribute to the development of a lisp.  Examples include: missing teeth, anterior open bite, underbite, cross bite, permanently crooked teeth, cleft palate, and fistulas.  

    • Oral Myofunctional Disorders (OMD) can be the root cause of these anatomical anomalies. For example, an abnormality in the shape of the palate or crooked teeth can be the result of low tongue resting posture (secondary to prolonged use of a pacifier or a tongue tie).

  • Utilizing Different Dental Appliances: The utilization of a bite-plate, dentures, retainers, and other appliances can cause a temporary lisp. This occurs because the place where the tongue anchors is more slippery given the appliance.

Diagnosing a Lisp: The Speech Therapy Evaluation

A lisp is often not hard to recognize; however, a thorough speech evaluation is necessary to determine the possible causes for a lisp, the type of lisp, and the proper treatment plan.

Case History: The speech therapist (SLP) will gather all pertinent information about the client, including medical history, past speech history, and current concerns.

Oral Peripheral Exam: The SLP will examine the structures of the mouth, including the tongue, teeth, hard and soft palate, tongue, jaw, and lips. These structures play a critical role in producing sounds and are therefore an important part of the examination.

Observation: The SLP will listen to the client speak and identify speech-sound errors, including lisping. The therapist will take note of which sounds are impacted by the lisp, as well as determine whether any other sounds are articulated incorrectly.

Standardized Assessment: The SLP may use a formal or standardized assessment to evaluate overall speech-sound production. These assessments may involve tasks where the individual is asked to say specific sounds, words, sentences, or engage in conversation. The SLP will listen for errors in speech sounds, including lisp-related errors.

Language Assessment: The SLP may informally or formally assess the client’s language skills. This assessment aims to exclude any language delays or disorders; however, it is important to note that lisping itself is not indicative of a language impairment.

Individualized Therapy Plan to Fix a Lisp

A personalized treatment plan includes some or all of the following:

  • Instruction in Phonetic Placement: The placement of the jaw, lips, and tongue are described to accurately produce the sound correctly.

This plan includes:

Stabilizing the jaw: In order to produce most sounds, the jaw must be stable. For /s/, for example, there is a gap between your top and bottom teeth (about 1 mm) and a gap between the sides of your teeth (a little more than 2 mm). Tooth props such as straws may be used to teach where the jaw should lie when producing each sound.

Stabilizing the tongue: In order to produce the sibilants, the back of the tongue must be anchored on the back molars. The front of the tongue is in contact with the palate (placement is different depending on the sound being produced).

Creating, narrowing, and refining the tongue groove: In order to produce sibilants, air must pass over the tongue. (The narrowness or wideness of the groove depends on the specific sound being produced.)

  • Exercises involve strengthening oral muscles to improve sound production.

  • Compensatory Strategies entail teaching techniques to modify speech patterns and minimize the lisp. Strategies are sometimes taught if you have an anterior open bite, underbite, crossbite, permanently missing/crooked teeth, clefts, or fistulas.

  • Collaboration involves partnering with other specialists, such as dentists and orthodontists, when required. If conditions such as crossbite, anterior open bite, underbite, etc. are corrected, compensatory strategies may become unnecessary, and the accurate production of sibilants can be achieved without them. This is because the structures of the mouth have now been corrected so proper positioning can now take place.

  • Production of the sound in varying contexts involves perfecting the pronunciation of the target sound in different situations. This requires a systematic approach which entails mastering the sound initially in isolation, then progressing through syllables, words, phrases, sentences, and finally integrating it into natural conversation.

Speech Therapy Techniques for Correcting an /s/ Lisp

Speak with Stephanie speech therapist helping adult client correct a lisp in Wilmette, Illinois

1. Use a mirror

Using a mirror is a great way to produce the /s/ sound especially if you produce the sound with your tongue between your teeth. When producing the /s/ sound, your goal is to keep your tongue behind your teeth, but not touch your teeth.

Look in the mirror and smile, keep your mouth open with your teeth close together (but not touching). Your tongue should touch behind your teeth. When you produce /s/, the air should flow smoothly over your tongue and out of your mouth when the tongue is in the proper position.

Attempt to do this exercise 10 times a day for a two weeks or until you can make the /s/ sound while keeping your tongue behind your teeth.

Once you can achieve this, practice the /s/ sound in syllables. Once achieved, move onto words, phrases, sentences, and finally conversational speech.

2. Exploding T- Technique

Repeat the /t/ sound quickly and repetitively like this /t-t-t-t-t-t-t/, followed by a prolonged /sssssssss/. It should sound something like this /t-t-t-t-t-tsssss/.

Once mastered, you can begin practicing words that end in /ts/ like "eats," "beets," "meets," "hits."

Finally, you can bridge this practice to help you produce the /s/ sound at the beginning of words by having an ending /ts/ sound next to a word that begins in /s/.

For example:

He hits even

He hitssssss even

He hitsssss seven

How long it Takes to Fix a Lisp

Speak with Stephanie speech therapist helping child client correct a lisp in Evanston, Illinois

Finding a straightforward answer to this question isn't easy. Some speech therapists say that it depends on the severity of the lisp, but from my experience, the longer the lisp has gone untreated, the more therapy and time it may take to remediate. For example, a 10-year-old who's been lisping for a while will probably need more therapy than a 5-year-old. That being said, older children and adults tend to be more motivated for therapy. So, the dynamics operate in a dual direction.

Speech therapy intervention for a lisp is usually short-term and successful. The more you practice, the quicker progress will be.

Oftentimes, speech therapists will recommend scheduling regular sessions over several months to ensure good results. These sessions are typically one-on-one and last anywhere from 30-45 minutes. Attending regular speech sessions and engaging in practice after sessions is important in order to make progress.

Your speech therapist will create an individualized treatment plan that focuses on the sounds giving you difficulty. You will receive helpful tips and strategies to produce these targeted sounds.

How Speech-Language Pathologists can help you or your child with a lisp

If you suspect either yourself or your child may be exhibiting signs of a lisp, it may be time to seek help from a speech therapist. Lisps can present challenges in various aspects of life, including academic, professional, and social environments. Individuals, both young and old, may become aware of their speech difficulty and instinctively avoid certain sounds, such as /s/, /z/, /sh/, /ch/, /t/, and /d/, that are affected by the lisp.

For instance, a child experiencing difficulty with the sound "s" might say the word "pen" to avoid the /s/ sound in "pencil." Addressing a lisp through speech therapy can lead to significant improvements in academic performance, professional interactions, and social confidence. By working with a skilled SLP, individuals can gain the ability to express themselves articulately and confidently, enhancing their communication in a variety of contexts.

Frequently Asked Questions

What causes a lisp?

We do not always know the cause of a lisp for every person with a lisp; however, some known causes for lisp include: incorrect practice, hearing loss, and structural irregularities in the structures of the mouth that assist with speech production (for example, teeth, tongue, soft palate).

At what age should a lisp be corrected?

In a public school, many speech therapists may begin seeing children with lisps in second grade. A speech therapist in a private practice can begin treating lisps much earlier. Lateral lisps should be treated as soon as possible as this is not normal trajectory for speech development.

Can adults correct a lisp?

Yes, adults (and children) can correct a lisp with speech therapy.

Is it possible to have a temporary lisp?

Some dental procedures and appliances (for example, retainers and dentures) can cause a temporary lisp.

Is a lisp a sign of a speech disorder?

A lisp is a sign of a speech disorder.


About the author:  

Stephanie Jeret is a Speech-Language Pathologist and the owner of Speak with Stephanie LLC. She obtained her Bachelor's and Master's degree from the City University of New York. She has practiced speech therapy in a number of settings including outpatient rehabilitation, telepractice, skilled nursing facilities, schools, and a private practice. She specializes in the evaluation, diagnosis, and treatment of a variety of communication disorders including articulation disorders, receptive/expressive language disorders, and fluency disorders. Information is available by emailing her at or by visiting



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