If you can find the right analogy, explaining anything becomes easy. Here is a wonderful analogy of spam emails to explain your role as an Ah counter. Notice how linking the analogy makes the introduction short yet so effective.
Imagine if Gmail and other email service providers did not filter the spam emails we received. Our inbox would always remain filled with useless emails making it tough for us to find the right and useful messages.
Well guess what, unknowingly while speaking on stage, we spam our speeches too with filler words such as ah, um, err, you know, like etc and they make it tough for our audience to get our messages as well. So, as an Ah Counter today, my job is to filter all those filler words spamming your speeches. I will keep a track of them and present my report towards the end of the meeting.
Over to you the General Evaluator.