The soul is... but an empty word, of which no one has any idea, and which an enlightened man should use only to signify the part in us that thinks... - Julien Offray de La Mettrie

Among animals, some learn to speak and sing; they remember tunes, and strike the notes as exactly as a musician. Others, for instance the ape, show more intelligence... would it be absolutely impossible to teach the ape a language? I do not think so.

[W]hy should we divide the sensitive principle which thinks in man? ...For a thing that is divided can no longer without absurdity be regarded as indivisible.

As a violin string or a harpsichord key vibrates and gives forth sound, so the cerebral fibres, struck by waves of sound, are stimulated to render or repeat the words that strike them.