Writing is not speaking. What looks good on paper nearly always sounds turgid and long-winded when spoken aloud. You don’t know if what you’ve written is any good until you actually say it. The problem for many presenters is that the first time they do say it aloud is in front of their audience, doing it for real. This is not the ideal time to learn that what you’ve written doesn’t actually sound that good.
The solution is to make sure you give yourself enough time to practise saying your presentation out loud – preferably to another living being. You will immediately notice the things that look OK on paper but have no resonance when you say them. If you have to do a lot of presentations, it might be worth getting voice-recognition software and dictating your presentation. That way, you start off with spoken language, rather than trying to turn writing into speaking.
In any event, aim to write more simply than you would for, say, a report. Take, for example, Steve Jobs’ MacWorld speech in 2007. His sentences were, on average, just 10 words long. His vocabulary was extremely simple: only 3% of his words were three syllables or longer. This means that 97% were words like ‘hand’, ‘heart’, ‘head’ – concrete words that people find much easier to process than abstract monstrosities like “incentivisation”. On its own, the odd ‘receptivity-cluster’ may not seem too offensive (it is), but they can soon mount up and leave your audience not energised but tranquilized.
Remember: writing is not speaking. One of the most crucial, most effective, most rousing speeches ever made in British history was recently run through a computer programme for assessing students’ writing. It failed resoundingly – too simple, too repetitive, lacking in style. The speech? Churchill’s “We shall fight them on the beaches.”