Here i have given with the examples 

1. When people laugh, they relax and they open up. They are more receptive to your ideas.

2. Humour allows for great juxtaposition.

3. People are more likely to accept your insight and sage like wisdom if you can laugh… at yourself.

Few things get people to drop their guard more than humour. If you want your audience to consider a new perspective, one of the best ways to get them to open themselves up to it is to first get them laughing.

If you are interested in trying this in one of your own speeches then let me suggest this. First, write your speech out as a serious speech. Focus on your message and not your humour. Once you’ve got a great message, you can then go back and look for places to add humour to the speech.