Powerful speeches eliminate the words and phrases that weaken language. And these little phrases are everywhere: People use "perhaps" and "I think that maybe" almost without realizing it. Powerless speakers use "It seems like" and "you know." Their language is filled with modifiers like "kind of" and "sort of." Compare the difference between saying "I hope I can get that done for you" and "I know I can get that done for you." One little word can make a great difference. If you feel strongly about something, use strong words. "I think" is not strong. It automatically weakens what follows, even though what usually follows is an assertion. "This is the best solution" is much stronger than "I think this is the best solution."
Social scientists at Duke University have been able to pinpoint a specific pattern that identifies powerless speech. Intensifiers such as very, definitely, and surely do the opposite of what they are supposed to do: They weaken the descriptive adjective that follows by not letting it stand on its own. "The car is fast" is a stronger statement than "The car is very fast."
Powerless speakers also hesitate often, relying on fillers such as "uh," "umm," and "well..." to get them from point to point. They are overly polite, and often use "sir" and "please." Obviously, politeness has its place, but if you are too polite, you seem timid and worried that what you are going to say will offend. And if you seem to have doubts about what you have to say about your subject, your audience won't be far behind.