Law schools do one thing superbly well: they teach the intellectual skills of reasoning, of distinction drawing, of deductive and inductive logic, of anlysis and synthesis. These are heavily verbal skills, at least in the context in which lawyers employ them, and students are tested for their mastery of these skills by written examinations. If one does well, he or she is placed on the law review, where these particular skills are honed even further.
Reed, John W. "Bad News and Good News." Int'l Soc'y Barristers Q. 10 (1975): 159-69.