Demosthenes started to learn rhetoric because he wished to take his guardians to court and because he was of "delicate physique" and could not receive gymnastic education, which was customary. In "Parallel Lives," Plutarch states that Demosthenes built an underground study where he practised speaking and shaving one half of his head so that he could not go out in public. Plutarch also states that he had "an inarticulate and stammering pronunciation" that he overcame by speaking with pebbles in his mouth and by repeating verses when running or out of breath. He also practised speaking in front of a large mirror.