How jaw stability affects speech clarity
Why some sounds need a high, steady jaw and others a lower one, and what can happen to speech when the jaw is not stable.
Transcript
Jaw stability is really important in speech clarity, and jaw stability is governed by the range of motion and the adaptation of the tongue where it sits within the mouth. Here’s an example of why. Some sounds are made with a high jaw, so we do not need to open our jaws much in order to make the tongue and/or the lips do what they need to do. This height is just a couple of millimeters.
T-t-t-t-t, da-da-da-da-da, sss. And vowels like eee and other sounds are made with a much lower jaw. These are over a centimeter. Ca, ca, ca, ca, ca.
La, la, la, la, la. Ah. And our mouth needs to be able to move between these different jaw heights, and within that, the tongue needs to be able to move up to the front, up at the back, or up in the middle and brace up against the teeth, as well as movement of the lips in, in and out, and up and down for bilabial sounds. When the jaw height is compromised or when there is movement side to side, this affects the tongue and lips ability to do that, and that can result in speech sound errors, lateral lisps, difficulty saying sounds like R, um, and often just in a general lack of clarity or something that people might consider as mumbling.