People say that writing is essential for organizing their thoughts. Most people are indeed more comfortable writing out their speech before giving it. However, this can be a trap for the beginner who doesn’t fully appreciate the difference between the written word and the spoken word.
The written word has tools like commas, periods, paragraph breaks, and question marks. It is designed to be read by the eyes, which can easily handle sentences twenty words long. The spoken word relies on your entire body, but primarily your voice, tonality, and pauses. It is designed to be “read” by the ears, which is accustomed verbal chunks that are 5 – 7 words long. Moreover, while you may be perfectly comfortable using certain words in your speech draft, such as vehemently, you may stammer if such a word were to escape your lips in front of 100 people. The speaker who doesn’t appreciate this difference between writing to write and writing to speak does so at his own peril.
The aspiring writer/speaker would do well to read The Elements of Speech Writing and Public Speaking by Jeffrey Scott Cook. Cook delves deep into the technical aspects of speech writing and tells you how to script and outline your speech for any occasion and how to deliver those carefully crafted speeches. There’s a great chapter on how to build oratorical power by the use of similar words to open sentences (anaphora) and use of sentence fragments to quicken the pace (asyndeton).
For more on how to make a seamless transition between your written draft and your oral product, check out Bernie Bulkin’s article on Speaking From A Text.