Demosthenes was a prominent Greek statesman and orator of ancient Athens. His speeches exemplify the pinnacle of Greek oratory for general intellectual prowess, form, content�and delivery.
Plutarch has this to say about Demosthenes:
�Hereupon he built himself a place to study in underground (which was still remaining in our time), and hither he would come constantly every day to form his action and to exercise his voice; and here he would continue, oftentimes without intermission, two or three months together, shaving one half of his head, that so for shame he might not go abroad, though he desired it ever so much.�
What image we retain of the great orator is that he overcame his feeble physical natural, to include a speech impediment, by constant discipline and training, exercising his diction by practicing with pebbles in his mouth.
Dionysius� essay on Demosthenes shows his predilection for him, by declaring him the champion among champions, including none other than the great Plato. This same essay, incidentally, contains scathing criticism of Plato�s writing.