What Causes A Lisp: An Accurate Guide

Lisp is a speech impediment associated with making sounds with S or Z. Though lisps usually go away on their own during their childhood years, sometimes they persist and will involve calling the attention of professional treatment. There are many factors identified to answer what causes a lisp in people1.

No known causes have been found to determine how a lisp is caused, but some researchers and professionals speculate that it could have its origin in using pacifiers for too long. Prolonged usage of pacifiers strengthens the tongue and lip muscles, increasing the chances of lisping2. There is a need to know that using a pacifier doesn’t always involve developing a lisp.

To understand what causes a lisp, one must identify factors related to the use of something as measly as a pacifier.

Young children tend to lisp as they learn how to talk as it is the most common speech impediment. 23% of the patients who consult speech-language pathologists have lisps.

A. About Lisps

Speech problems like the development of lisps could have a phonetic origin3. A child could have physical difficulty acquiring proper placement of their lips, tongue, or jaw.

It sometimes varies from speech sound disorders that have a linguistic origin. In this scenario, the child can differentiate between two individual speech sounds but is still learning to tell the difference between two sounds (run – won).

Ankyloglossia, or just “tongue-tie” in simple terms, is a condition where a part of the tongue is attached to the bottom of the mouth, which restricts its movement.

There are different kinds of lisps that have been identified by professionals in research and clinical settings.

1. Frontal Lisp

Speech, or any sound known to human beings, is primarily created by several combinations of the tongue’s proper positioning in the mouth and the ejection of air.

Here, the tip of the tongue nudges against or the tongue protrudes between the teeth positioned in front, obstructing airflow. As a result, “s” and “z” consonants in words are frequently vocalized as “th” sounds.

For example, words like “pass” and “sleep” would be pronounced as “path” and “sheep”. The frontal lisp is one of the most commonly found lisps.

2. Lateral Lisp

Lateral lisp occurs when the air that passes over the sides of the tongue into the cheeks results in a lateral lisp which leads to the production of several sounds like /s/, /z/, /ch/, /ch/ /ch/, and /DJ/.

Parents describe their child’s speech as “mushy” or “slushy.” Children with a lateral lisp will not outgrow it and will require speech therapy as a necessity.

3. Palatal Lisp

A palatal lisp is said to be associated with a soft palate, which is the roof of one’s mouth. Rolling their tongue too far back could cause the tongue to touch against the soft palate, leading to the development of palatal lisps4.

4. Dental Lisp

This form of lisping is similar to frontal lisping, with the difference being that in frontal lisps, what causes a lisp is the protrusion of the tongue against the front teeth, and in dental lisps, the person pushes their tongue against the front teeth.

Like frontal lisps, dental lisps appear in children who are just learning how to form coherent sentences but do not persist past the age of 4.

5. Interdental Lisp

Here, the child tries to produce /s/ and /z/ sounds with the tongue sticking out between the front teeth. It results in a “the” sound similar to the sounds found in children with a frontal lisp.

The difference between interdental lisp and dental lisp is that the former produces a “th” sound, and the latter produces a more muffled /s/ and /z/ speech sound.

B. Physiological Aspects

Several physiological reasons also answer the question of what causes a lisp5.

For example, ear, nose & throat specialists haven’t ruled out the possible impact of large tonsils and nasal obstructions like allergies and stuffy noses in children on the development of lisps.

A lot of the space at the back of the throat could be taken up by enlarged tonsils, the place where the base of the tongue normally sits.

This affects the tongue placement and tends to push the tongue forward and leads to the development of “mouth breathing” where the mouth, instead of resting closed, rests open and plays a big part in what causes a lisp.

Orthodontists and dentists have agreed on the fact that genetics tend to contribute to the placement of the jaw and teeth in a person. The positioning of a person’s teeth is influenced by forces of the lips, cheeks, and tongue.

So, when the tongue pushes forward (also known as “tongue thrust”), leads to the formation of an overbite where the front teeth are pushed more towards the front. In such cases, the behaviors that cause the “tongue thrust” are treated first.

C. About Speech Sound Disorders

According to ASHA, “speech and sound disorders are an umbrella term referring to any difficulty or combination of difficulties with perception, motor production, or phonological representation of speech sounds and speech segments—including phonotactic rules governing permissible speech sound sequences in a language.”

To understand what causes a lisp, we have to know that speech and sound disorders can be functional or organic. A lisp can be classified as a functional speech disorder. These disorders are epitopes of functional neurological disorders.

1. Organic Origin

Speech and sound disorders that have an organic origin are usually results of motor or neurological disorders.

Some of the organic disorders are:

a. Childhood apraxia

Children with childhood apraxia of speech are not able to say much or move their tongue muscles the way they want them to.

In normal development, the messages come from the brain to the mouth to produce speech sounds. In a developmental speech disorder like childhood apraxia6, normal speech development is hindered as these inter-muscular messages do not get passed on correctly.

b. Dysarthria

It is a speech disorder characterized by muscle weakness. It is a motor speech disorder that occurs because of damage to the nervous system and the muscles used in speech processes become weak, paralyzed, or completely damaged.

c. Cleft Lip/Palate

Children with cleft lips or palates tend to develop softer palates and sound very nasal. A delay is experienced by such children in the development of speech sounds.7

The tendency to produce nasal sounds is due to the soft palate not being able to close off the mouth and the nose while speaking, letting air escape from the nose.

d. Sensory/Perceptual Disorders

Hearing impairment, for example, makes it harder for children to learn how to talk or understand speech, leading to speech delay. This eventually spills over to increasing problems in social skills, success in school, and reading.

Such children may have problems using words that have /s/, /ch/, /f/, /t/, or /k/ as they are soft sounds that are difficult to hear. This defect may also help in answering the question of what causes a lisp.

2. Functional Speech & Sound Disorders

These disorders are related to the motor production of speech sounds and also include the ones that are related to the linguistic origins of speech production.

Archaically, functional speech disorders were referred to as articulation and phonological disorders. Difficulty in producing individual speech sounds (distortions and substitutions) are categorized as articulation disorders.

In contrast, phonological disorders are centered around predictable, rule-based errors like fronting, stopping, and final consonant deletion that affect multiple sounds.

To understand the underlying causes of what causes a lisp, when a speech sound issue is suspected, or as part of a thorough speech and language examination for a kid with communication concerns, screening is performed.

The goal of the screening is to identify people who need more speech-language evaluations and/or referrals to other professionals.

Speech and language therapy can help with speech sound and general communication issues caused by a lisp.

Working on these areas can help a client create coping skills to help them overcome their lisp and enhance their speech fluency. Because a lisp is ingrained, the more work a client can do outside of speech and language therapy sessions, the faster he or she will progress.

D. Speech Therapy

Speech and language therapy can assist a client to improve their communication skills and build coping mechanisms for their lisp by comprehending what causes a lisp.

As a result, the client may gain confidence and become more fluent in their speech production. A client may also be able to alter the manner they make a particular speech sound.

1. Speech-Language Pathologists

In most cases, speech pathology treatments for lisps in young children are short-term and effective.

Speech and language pathologists have differing perspectives on what causes a lisp and how difficult or simple it is to assist a child to overcome a lisp, as well as how long it normally takes.

From toddlers to adults, speech-language pathologists work with people of all ages. They help people with a variety of speech and swallowing issues.

2. What does a Speech-Language Pathologist do?

If your child has a lisp after the age of five, you should consult a speech-language pathologist (SLP), sometimes known as a speech therapist.

A speech-language pathologist will use articulation exercises to help a person with a lisp pronounce particular sounds properly and also help the people involved to get an idea of what causes a lisp.

Some techniques used are:

1. Awareness

A speech-language pathologist can help your child become more aware of appropriate and incorrect pronunciation by modeling it and then having him or her identify the correct method of speaking.

2. Placement of the Tongue

As tongue placement is so important in lisping and answering what causes a lisp, in speech therapy, the SLP will work with you or your kid to become more conscious of where your or their tongue is when they try to make various sounds.

3. Assessing Words

The speech therapist will have the child practice single words to obtain a sense of how their tongue is positioned when they try to pronounce different consonants.

Some other techniques that are used to help with lisps include drinking through a straw and practicing words and phrases that would eventually lead the child to use them in regular conversations without lisping.

E. Conclusion

Some (but not all) children generate interdental or dentalized/s/ and /z/ sounds until they are around four (4) years old, which is a normal developmental phase. Neither lateral nor palatal lisps, on the other hand, are part of the normal developmental process.

A skilled speech-language pathologist/speech and language therapist should assess the speech of a kid with a lateral or palatal lisp as soon as possible. An SLP/SLT can assist both adults and children to help them understand what causes a lisp, but successful self-help is uncommon.

For more information, visit the American Speech-Language-Hearing Association.

Reviewed by: Omejua Chimdike (B.MLS), Biomedical Scientist (UNN)

About Omejua Chimdike .G.

A talented, knowledgeable and certified medical laboratory scientist with experience in carrying out standard laboratory practices (tests) on patients of various cultural backgrounds with the aim of researching and developing diagnostic approaches that will aid in the diagnosis of diseases and increase patient outcomes to treatment. Currently, working as a research scientist at Everight Diagnostic Laboratory Services limited (Centre for Research and Molecular Studies), Nigeria.

LinkedIn: https://www.linkedin.com/in/chimdike-omejua-520859199

WordPress : https://omejuachimdikeacademia.wordpress.com/

Gmail: chimdike.omejua.188155@unn.edu.ng

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  1. Lockenvitz, Sarah, Judith Oxley, and John Tetnowski. “The experience of stigma in adults who lisp: A thematic analysis.” Journal of Interactional Research in Communication Disorders 13.2 (2022). ↩︎
  2. Whitaker, Melina Evangelista, et al. “Relationship between occlusion and lisping in children with cleft lip and palate.” The Cleft palate-craniofacial journal 49.1 (2012): 96-103. ↩︎
  3. Harrington, Jonathan, et al. “The phonetic basis of the origin and spread of sound change.” The Routledge handbook of phonetics. Routledge, 2019. 401-426. ↩︎
  4. Dagenais, Paul A., Paula Critz-Crosby, and June B. Adams. “Defining and remediating persistent lateral lisps in children using electropalatography: Preliminary findings.” American Journal of Speech-Language Pathology 3.3 (1994): 67-76. ↩︎
  5. Smith, Brian Cantwell. “Reflection and semantics in Lisp.” Proceedings of the 11th ACM SIGACT-SIGPLAN symposium on Principles of programming languages. 1984. ↩︎
  6. American Speech-Language-Hearing Association. “Childhood apraxia of speech.” (2007). ↩︎
  7. Wellman, Beth L., et al. “Speech sounds by young children.” (1931). ↩︎

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