Litigants spoke on their own behalf, although occasionally using speeches prepared by trained professionals; skillful rhetoric was necessary in order to sway a jury. The speeches written by several noted orators survive today, those of Lysias, Lykourgos, Hypereides, Antiphon, Demosthenes, Aeschines, and Isokrates. Of these, perhaps the best known for his ability in forensic speaking was Demosthenes, a statesman who led Athenian opposition to the rising power of Philip of Macedon in the 4th century B.C.
Demosthenes' skills as a public speaker in the assembly were honed by training and considerable self-discipline:
They say that when he was still a young man he withdrew into a cave and studied there, shaving half of his head to keep himself from going out; also that he slept on a narrow bed in order to get up quickly and that since he could not pronounce the sound of R he learned to do so by hard work, and since in declaiming for practice he made an awkward movement with his shoulder, he put an end to the habit by fastening a split or, as some say, a dagger from the ceiling to make him through fear keep his shoulder motionless. They say, too, that as he progressed in his ability to speak he had a mirror made as large as himself and kept his eyes on it while practicing, that he might correct his faults; and that he used to go down to the shore at Phaleron and address his remarks to the roar of the waves, that he might not be disconcerted if the people should ever make a disturbance; and that because he was short of breath he paid Neoptolemos the actor ten thousand drachmas to teach him to speak whole paragraphs without taking breath. (Plutarch, Moralia 844)
No trial took more than a single day. Time was therefore allotted to the speakers according to a set schedule and measured carefully by means of klepsydrai (waterclocks): "There are klepsydrai that have small tubes for the overflow; into these they pour the water by which the lawsuits must be conducted" (Aristotle, Athenian Constitution 672).
A single example has survived, dating to about 400 B.C. It runs for only six minutes and thus represents a short speech. The preserved speeches of Demosthenes and other orators, whether on public or private matters, run much longer, and there must have been larger vessels to time them. Testimony of witnesses and citation of legal documents did not count against one's speaking time, and there are repeated requests in the preserved speeches for the water to be stopped. Experienced orators would keep an eye on the jet of water at the outlet, and as the pressure fell they would bring their speech to an end just as the last drops ran out.