And his style is deeply marked by that want of feeling for the exquisite, that dulness of edge, that bluntness of stroke, which is the common note of all German literature, save a little of the very highest.

In conversation we do not insist on constant precision of phrase, nor on elaborate sustension of argument.

Apostrophe is made natural by the semi-dramatic quality of the situation.

Even vehement hyperbole, which is nearly always a disfigurement in written prose, may become impressive or delightful, when it harmonises with the voice, the glance, the gesture of a fervid and exuberant converser.

Hence Diderot's personality invested his talk, as happened in the case of Johnson and of Coleridge, with an imposing interest and a power of inspiration which we should never comprehend from the mere perusal of his writings.
His admirers declared his head to be the ideal head of an Aristotle or a Plato.