Q: I have a student with a lateral lisp whose does not have proper jaw alignment. The jaw at rest and during speech is moved over to the right. My thoughts are that the misalignment of the jaw is causing lateralization of the sibilants. Is this correct? What are your thoughts?
You are right. The jaw has to be in a stable midline position to produce a correct midline sibilant. I divide lateral lisps into several categories according to whether the jaw or the tongue are in error:
- Jaw Lateralization Lisp: Lateral lisps that are caused by jaw lateralization left or right. In this case the tongue is still creating a midline groove, but the sound is going out tot the side because the jaw is shifting that way.
- Unilateral Lisp: Lateral lisps that are caused by misplacing the tongue groove to the left or right. The jaw is still in a stable midline position. The cheek pulls out of the way on the side to which the air is directed.
- Bilateral Lisp: Lateral lisps that are caused by elevating the midline of the tongue so that the air escapes out both left and right sides. The jaw should kept stable at midline. The cheeks pull laterally on both sides to allow the air to escape on both sides simultaneously.
- Omni Lisp: Those that are made with no tongue groove at all, and by articulating no part of the tongue against the palate. The jaw is at midline. The airstream escapes out the entire front of the mouth from L to R. It sounds lateral because some of the sound is.
- Any combination of the above.
Your job in the assessment is to determine whether the jaw is moving to one side (a movement problem), or whether a malocclusion is causing the jaw to sit to one side (a structural problem).
If the jaw is simply moving to one side, you can stabilize it by having him bite with the molars on to a straw or coffee stirrer. Use your hand to move the jaw into position as the child bites. He then can learn to make his sound with the jaw in correct position. Then teach him to hold the position correctly with the stick out of the mouth.
A malocclusion is, as you know, a structural problem. The solution is to fix jaw structure with orthodontia or surgery. In cases where the jaw cannot or will not be fixed with orthodontia or surgery, we teach the client to make the best sound he can, given his structure. Van Riper called this the process of teaching “compensation.”