Can speech therapy correct a lisp?

What is a lisp?

Lisping is one of the most common and most well-known articulation disorders resulting from abnormal tongue positioning, which causes a perceived sound distortion. It is estimated that 90% of speakers who have some kind of articulation difficulty exhibit some degree of lisping behavior1. While lisping most frequently impacts “s” and “z,” it can affect other sounds as well, such as “th” and “sh.”

Lisping is considered a mechanical issue that may be either structural, from an overbite or underbite, or behavioral, from a tongue thrust. Factors that impact it includes tongue weakness or jaw instability, as a lowered jaw impacts the ability of the tongue to lift. Typically, jaw instability and tongue weakness coexist when a lisp is present. However, causes are nearly always behavioral and can be treated with skilled therapy.

What are some common types of lisps?

The most common and well-known variety is a “frontal lisp” or “interdental lisp.” Most people think of a frontal lisp as a “th” substitution, as in the production of “thun” for “sun .” However, this is not the case. The tongue does not protrude as far out as during a “th” production. Instead, it may not even protrude, positioned on or between the teeth, and is frequently visible during “s” production. Frontal lisps are nearly always behavioral in nature, not often resulting from structural issues. As a result, they are not a concern for children below 5. Following age 5, it is considered disordered and requires skilled therapy to treat.

Another common type of lisp is known as a “lateral lisp.” This is never developmentally appropriate, meaning that it is disordered in a child of any age and must always be treated with skilled therapy. It results from a flattened tongue so that airflow, rather than moving in a forward trajectory, emits out the sides of the mouth, causing a “slushy” sound. Treatment of lateral lisps involves an emphasis on lifting the tongue to streamline airflow. Ensuring the child’s self-awareness and ability to monitor their speech is also essential during treatment.

Why should a lisp be treated in speech therapy?

While overall intelligibility is not as significantly impacted as with other articulation disorders, the effects of a lisp often have social-emotional ramifications. One study by Ellen-Marie Silverman indicated that lisps draw negative attention and impact perceptions relating to intelligence, personality, and likability.2 The phenomenon of lisping impacts the perceptions of others and the self. In a study by Veríssimo et al., participants who presented with lisps felt insecure and that their speech disorder negatively impacted their social life or work.3

Many parents first seek out speech therapy in elementary school when their child begins to feel shame or experiences bullying related to their speech. Then, the child, parent, and speech therapist can work together to resolve the issue. Following articulation therapy, children are proud of their speech and confident in their ability to communicate with their peers.


  1. Fairbanks, G. (1940) Voice and Articulation Drillbookt. New York: Harper and Row.
  2. Silverman, E. (1976). Listeners’ impressions of speakers with lateral lisps. Journal of Speech and Hearing Disorders, 41(4), 547-552. doi: 10.1044/jshd.4104.547
  3. Veríssimo, A., Van Borsel, J., & de Britto Pereira, M. (2012). Residual /s/ and /r/ distortions: The perspective of the speaker. International Journal of Speech-Language Pathology, 14(2), 183–186.

Kat Winger, M.S. CCC-SLP

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