Q: I have heard you say that jaw sliding to the left or right can cause one type of lateral lisp. I have also heard you say that this type of jaw instability is seen in children with dysarthria. Are you saying that a lateral lisp is a form of dysarthria?

Excellent question!

No. I am not saying that a lateral lisp is a form of dysarthria.

I am saying that clients with expressive speech deficit often have problems in jaw stability, and that these problems can range from mild to severe.

Mild

On the mild end are those clients who slide the jaw left or right during production of a specific phoneme, like sliding it to the left on an S, or a Z, or an R.  These clients keep their jaws at midline the rest of the time.

Severe

On the severe end are those clients with dysarthria who slide the jaw left and right all throughout the course of speech. This type of continual shifting takes the upper and lower lips out of their regular alignment. It also takes the tongue away from its regular midline alignment with the palate.  The types of lip and tongue misalignments caused by an unstable jaw cause tremendous distortion of speech.  This was noted years ago by one of our greatest speech scientists ––

“Although jaw movement is very slight during the production of normal speech, inadequate, inappropriate, or sluggish movements may result in severe articulatory defects” (Zemlin, 1968, p. 324).

Reference

• Zemlin, W. R. (1968) Speech and Hearing Science: Anatomy and Physiology. Englewood Cliffs: Prentice-Hall.