A lisp is a common speech sound disorder that is highly treatable across all age groups with targeted intervention. This difficulty involves the incorrect production of sibilant sounds, most notably the ‘s’ and ‘z’ sounds, due to misdirected airflow and improper tongue placement. Incorrect tongue positioning distorts the clear, sharp quality of the sound, which affects speech clarity. A speech-language pathologist (SLP) employs specific techniques to retrain the tongue muscles and develop the proper motor pattern needed for clear articulation.
Defining Lisps and Their Types
Lisps are categorized by the way the tongue interferes with the airflow required to make the ‘s’ and ‘z’ sounds. The most frequently encountered type is the interdental lisp, also known as a frontal lisp, where the tongue pushes forward between the front teeth. This tongue protrusion causes the sound to resemble the “th” sound. Interdental lisps are considered developmentally normal for very young children but typically resolve by age four or four and a half.
The lateral lisp occurs when the airflow escapes over the sides of the tongue instead of through a central groove. This results in a “slushy” or “wet” sound. The lateral lisp is not considered a typical part of speech development and usually requires intervention from an SLP. Other types include the dentalized lisp, where the tongue pushes against the back of the front teeth, and the palatal lisp, where the tongue touches the roof of the mouth.
Common Causes and When to Seek Help
Lisps often fall into categories of functional, structural, or physiological issues. Functional causes are habitual, arising from incorrectly learning to produce the ‘s’ and ‘z’ sounds during speech development. Structural factors can include issues like jaw misalignment, missing teeth, or malocclusion. Physiological issues like a tongue thrust, where the tongue habitually pushes forward, or a tongue-tie (ankyloglossia), which restricts tongue movement, can also contribute to a lisp.
For children, a professional evaluation is recommended if a lisp persists beyond the age of four or five, especially if it is a lateral or palatal lisp, which are rarely outgrown. The SLP conducts a thorough assessment of the individual’s articulation and oral motor function. This assessment determines the specific type of lisp and its severity, guiding the creation of a personalized treatment plan. Seeking help early is beneficial because the longer an incorrect motor pattern is practiced, the more effort is required to break the habit.
The Process of Lisp Correction Therapy
Lisp correction therapy, or articulation therapy, follows a structured, step-by-step process designed to retrain the muscles for accurate sound production. The first phase focuses on auditory discrimination, helping the individual recognize the difference between the incorrect lisp sound and the correctly produced target sound. This heightened awareness is achieved through listening activities and feedback mechanisms, which are foundational for self-correction.
Eliciting the Correct Sound
Once the sound distinction is clear, the next step is eliciting the correct sound in isolation. The SLP uses phonetic placement cues. These cues often include tactile feedback or visual aids like a mirror to show the proper tongue placement behind the teeth. Techniques such as the “exploding T” method, where the /s/ sound is shaped from a prolonged /t/, can be highly effective. Oral motor exercises may also be incorporated to strengthen the tongue and improve its control.
Generalization and Practice
After the sound is produced correctly in isolation, the therapy progresses through a hierarchy of increasing complexity. The individual practices the sound in syllables, then in single words, and subsequently in phrases and sentences. Consistent practice at home is integrated with the in-session work to reinforce the new motor memory. The final stage is generalization, where the newly mastered sound is consistently used in spontaneous conversation across all environments, marking the successful correction of the lisp.