Who are you trying to reach? What language do they speak?
If you only speak English, but the man who can solve all of your problems only speaks Japanese, is he any help?
If you're trying to teach children by locking them in a room for 5 hours of hard, boring classes, will you be successful?
If you're trying to show off how intelligent you are by dropping lots of ten-dollar words, will anybody understand what you're saying?
If your audience has a short attention span and low level of education, speak succinctly and simply. Short and to the point.
If your audience is children, find what appeals to them and make it fun.
If you're smarter than everyone in the room, try to understand that effective communication is not showing off your big words, but rather conveying ideas efficiently with the present audience.
Speak the language of your people and lift them up in the process. Because if you can't speak their language, you certainly won't be able to help them.