It is possible that they do a little better by opening their mouth, as the relative pressure difference working on the earedrums may be reduced a bit. Their main response would probaly to increase the distance if they can. Bone conduction is not much ifluenced by airborne sound, although it does play a role if the airborne part is reduced much, as with fighter jet and helicopter pilots. They need a helmet also to reduce noise the earmuffs does not take.
Dampening bone conduction involves reducing the transmission of sound vibrations through bone to the inner ear. Methods include padding or cushioning, adjusting pressure, using thicker materials, proper positioning, noise cancellation, and frequency filtering. These techniques help minimize the impact of bone conduction for improved comfort and clarity of audio transmission.