The art of public speaking began in ancient Greece over 2,000 years ago. Now, twitter, instant messaging, e-mail, blogs and chat forums offer rival approaches to communication - but none can replace the role of a great speech. The spoken word can handle various vital functions: persuading or inspiring, informing, paying tribute, entertaining, or simply introducing someone or something or accepting something. Over the past year, the human voice has helped guide us over the ups and downs of what was certainly a stormy time. Persuasion is used in dealing with or reconciling different points of view. When the leaders met inCopenhagen in December 2009, persuasive words from activists encouraged them to commit themselves to firmer action. Inspirational speeches confront the emotions. They focus on topics and matters that are close to people's hearts. During wars, generals used inspiring speeches to prepare the troops for battle. A speech that conveys knowledge and enhances understanding can inform us. The information must be clear, accurate, and expressed in a meaningful and interesting way. (流行病) announced, the idea of “swine flu” many people. Informative speeches from World Health Organization officials helped people to keep their panic under control so they could take sensible precautions. Sad events are never easy to deal with but a speech that pays tribute to the loss of a loved one and gives praise for their contribution can be comforting. Madonna's speech about Michael Jackson,after his death, highlighted the fact that he will continue to live on through his music. It's not only in world forums where public speaking plays an important role. It can also be surprisingly helpful in the course of our own lives. If you‟re taking part in a debate you need to persuade the listeners of the soundness of your argument. In sports, athletes know the importance of a pep talk (鼓舞士气的讲话) before a match to inspire teammates. You yourself may be asked to do a presentation at college or work to inform the others about an area of vital importance. On a more personal level, a friend may be upset and need comforting. Or you might be asked to introduce a speaker at a family event or to speak at a wedding, where your language will be needed to move people or make them laugh. Great speaking ability is not something we're born with. Even Barack Obama works hard to perfect every speech. For a brilliant speech, there are rules that you can put to good use. To learn those rules you have to practice and learn from some outstanding speeches in the past. The author thinks the spoken word is still irreplaceable because ______.