The current state of the thinking around mirror neurons is a little up in the air, but anyone who works with children will have seen behaviour that points to the theory holding some truth. Children huffing and puffing during bubble-blowing, partially in request, and partially in sympathy; and children with phonological disorder who cannot hear distinctions that they cannot realise themselves are two examples that spring to mind.
There is no other way for a child to make a theory about how an adult is moving their articulators other than to refer to their own anatomy. And if a part of that anatomy is disabled (as anterior movement of the tongue is when a child is using a dummy), then the dummy-using child will basically assume that we are all speaking through dummies as well. This has always been my inkling, and it has recently been confirmed in the paper “Sensorimotor influences on speech perception in infancy” published in November’s Proceedings of the National Academy of Sciences of the United States of America.
“This study indicates that the freedom to make small gestures with their tongue and other articulators when they listen to speech may be an important factor in babies’ perception of the sounds” Prof. Janet Werker, senior author of the study.
The study adds to the evidence that we can point to when we talk to parents about their use of dummies. Although the evidence is somewhat mixed regarding the impact of dummy use on language development, there is at least evidence that extended use is a risk factor for multiple ear infections. I’ve never met a Speech Therapist who didn’t recommend ditching the dummy as early as possible.