What is a model of how to write a speech given as a Chairman of an occassion?
To write a speech, you need to identify who your audience is. This expression is often used for writing of any sort, but when giving a speech, you will actually be talking to real live people, so it is important to know to whom you are talking. If you are the Chairperson of an event, are you fund raising; inspiring volunteers; explaining community service to children; introducing the guest speaker at the event? You may be able to see that each of these hypothetical suggestions of possible audiences are very different and require different styles and levels of speech.
Your next steps are to clearly explain your most important idea to the audience you will be speaking to, some advocate talking out loud before writing, and then write your explanation down as bullet-point guidelines or as whole sentences. Do this for each main point you want to make. Check for time to make sure your speech comfortably fits the time requirements--don't rush a lot of of information.
Then build good strong linking statements between your main points. Linking statements let the people you are talking to understand the relationships between points and how one point might affect another point. Then write an ending with a strong summary or call to action on the part of the listener. Lastly, write your Introduction to capture their interest and to state your purpose: We only know what we're being told after we've been told what we will be told (learning attaches to knowing).