Simplify the following text for a Grade 7 native English-speaking person.
Original: In an effect reminiscent of the earliest Cybermen 's mouths snapping open while speaking , the new Cybermen have a blue light in their `` mouths '' ( or `` teeth '' ) which blinks in synchronisation with their speech .
Simplified: The new Cybermen have a blue light in their `` mouths '' which blinks in synchronisation with their speech .