The voice, the lips
It is thought crude to move the lips when reading. We were taught to read by being made to read out loud then we had to unlearn what we were told was a bad habit, no doubt because it smacks overmuch of application and of effort. Which doesn’t stop the cricoarytenoid and cricothyroid, the tensor and the constrictor, muscles of the vocal cords and the glottis being activated when we read. Reading remains inseparable from this labial mimeticism and its vocal activity – there are texts that should only be murmured or whispered, others that we ought to be able to shout or beat time to.
Georges Perec, “Reading: A Socio-Physiological Outline”, Species of Spaces and Other Pieces, ed. and trans. by John Sturrock,(London: Penguin Books, 2008), pp. 174-175.