Machiavelli was purported to have advised that one should always tell the truth . . . because one day you may need to carry off a great lie and you'll want to be believed! He might have added that it is also hard work conceptually and destructive, occupying areas of the brain that could instead be used for something more productive. . . like learning pronunciation, for example. The 2011 research linked above by Porter, Brink and Wallace explores, among other things, the nonverbal "conflicts" that can be detected when lying in some contexts, in two locations on the face: corrugator supercilli (between the eyes) and depressor anguli oris (basically below the lips,) where the evidence of the extra effort seems to erupt to the surface momentarily. Pronunciation instruction at some stages, like learning of any kind, requires extreme concentration and focus of attention. It just happens that the facial muscles and underlying bone structures are also involved in producing sound, so that the effect of restrictions and distractions are magnified. It is more than a good analogy. If haptic-integrated pronunciation anchoring is being done on a multi-tasking, time share basis with other internal or external influences, it can be significantly undermined. (Research reported earlier looked at the susceptibility of haptic engagement to distraction, especially clutter in the visual field and body-based issues such as muscle stiffness or pain.) So, pay attention to quality of attention as evident on the faces of students. On this, don't be caught "lying down" on the job!