According to research by Lander and Caper at the University of Lancaster, a little more lipstick and work on your speech style may be in order. (Watched yourself on video lately when you ask a student "look at my mouth" as you provide a model?) Their study demonstrated unequivocally that your listeners' ability to understand you if they can see you can be enhanced considerably with a little tweaking. One feature that made words more easily understood, not surprisingly, was backing off from conversation style toward more declarative articulation, especially in times of potentially disruptive background noise. In addition, although other movement of facial muscles does play a supporting role or is synchronized with mouth and lip movement, it was the mouth that carried the functional load primarily.
|Clip art: Clker|
This is a particularly interesting problem in haptic work, in part because the eyes of the student are naturally drawn to the hand and arm movements. Consequently, you must be a bit more conscientious about how you articulate a model word, for example, as you do the corresponding pedagogical movement pattern, to be sure that students can also read you lip patterning as well. Record some of your work, turn off the sound and spend a little time trying to figure out what you were saying . . .
Obviously nothing to just "pay lip service to!"
Citation: Investigating the impact of lip visibility and talking style on speechreading performance - http://dx.doi.org/10.1016/j.specom.2013.01.003