http://agathe.gr/democracy/the_speakers.html
The Speakers 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 ... 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. ... 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.