Both speech and debate center around an activity that gets mentioned a lot in the U.S. but actually engaged in very seldom--dialogue. A good debater listens and responds intelligently to his opponent; a good public speaker establishes communication between himself or his group and whoever he's addressing.
It's all too common to watch debates between people so busy spouting their own opinion that their opponent goes unheard, or to listen to a speech so cluttered with platitudes and politically-correct language that it becomes meaningless. But you need not look too far back in history to find statesmen, academics and industry leaders able to clearly articulate their ideas in public forums without resorting to empty rhetoric or doctored statistics.
My kids aren't going into politics or economics, you might say. Why should they study speech and debate?
The fact is, most students would benefit greatly from focused study in these fields. Because while the public sphere is certainly the most obvious arena for putting these kinds of skills to use, the real benefit of speech and debate is to teach kids the arts of research, critical thinking, analysis, and effective communication.
Public speaking and debate aren't exactly the same thing. Traditionally, public speaking involves a single orator, while debate involves at least two speakers approaching one subject from different angles. There are some public speaking clubs still operating in the United States, but typically debate attracts the higher number of students, and really debate is simply a more advanced form of public speaking.
College debate clubs typically focus on parliamentary debate and moot court; these are fairly specialized law- and politics-based forms of debate and adhere to strict rules of form in addition to requiring high standards of content. Most high school students, however, practice either policy or Lincoln-Douglas debate.
Policy debate (or cross-examination debate, or team debate) centers around a resolution (such as, Resolved: That the United States should outlaw orangutangs) which students argue for or against using research and their own wits. Lincoln-Douglas is similar, except that it centers more broadly around a moral or idealist issue, like abortion or euthenasia.
Debaters have been known to obsess over their research, to spend unwarranted hours at the public library, to haul all their findings around in a big plastic box (okay, most of them do that), and to slick their hair to the side with Dep gel. But that doesn't mean you shouldn't get your kids involved. A good debater won't just snow the opposition with hard evidence; she'll learn both sides of the issue thoroughly enough to become conversant (often students are called on to defend both sides), and spend significant time cohering everything into a manageable and communicable position.
Public speaking is less rule-based than debate, doesn't require as much familiarity with opposing views, and generally involves only a single orator as opposed to speakers arguing back and forth. As a result, public speakers generally spend more time on rhetorical details, ensuring their speech will be both stirring and aesthetically pleasing. Francis Bacon thought young people should be trained in public speaking because it taught them how to remain calm under public observation.
There are more personal ways debate can improve students beyond the intellect. Intelligent students who struggle to express themselves will learn to present information and ideas clearly and effectively; blow-hards with a penchant for gabbing will be forced to remain succinct and support what they say with evidence and logic; and moderate students will refine their abilities to make a good argument in a cogent and (as Jon Winslow famously said) winsome manner.
All this talk of argument may put some parents off. But it isn't argument of the kind engaged in by combative siblings; it's argument of the old fashioned kind, the respectful exchange of ideas in a spirit of equality. This really is the whole crux of education--if students don't learn to communicate and defend their own beliefs, they haven't learned anything of much use. In fact, this is the point on which Christian education hinges, since it is the apologetic task of every believer to maintain a ready defense for those who challenge his faith.
There are local and national debate and public speaking leagues open specifically to home schoolers. Generally these mix hands-on practice with actual instruction, so kids aren't just groping in the dark. They have assignments, debate tournaments, and constructive criticism.
Genuine exchange of ideas seems to be an increasingly lost art, but if a society is to function as a free democratic republic, such exchange must be central to its framework. Even more important, as Christians we need to be able to understand opposing views, measure them against our orthodox beliefs, and respond to them intelligently and compassionately. Training in debate and public speaking can help us achieve both objectives.