I know this topic has been discussed before. But it happens a bit too often to not bring it up again. When flying instrument approaches in VFR conditions, it is the responsibility of the IFR traffic to make comprehensible radio calls. It should not be upto the VFR traffic in the pattern to figure out what the IFR pilots are talking about. Yesterday, a student and I were flying a practice approach to Runway 20 at my home field. Wind was calm, and the default runway is typically 20. I called 6 mile final, and then a 3 mile final. Another airplane was holding short on 20 for takeoff. Then we heard a Citation Execjet saying he was on a RNAV for 2 (opposite runway), but he did not give a position report. We broke off the approach and decided to circle to runway 2. The airplane waiting to takeoff asked how far the Citation was. There was no response. Then he too started taxiing to runway 2. While circling, I asked the Execjet what his position was, so that I can decide if I should extend our downwind. He responded with "we are at ICALO". I knew that is one of the initial approach fixes, but I didn't want to pull out a chart to look that up. I asked him again "how far are you?". His response: "we are approaching SOVVO". I was quite annoyed by now that this radio exchange had gone on for this long. I didn't want my student to be rattled by an ignorant jet jockey who does not know how to operate at an uncontrolled field. I repeated "I have no idea where that is, HOW FAR ARE YOU?". There was a long pause. Then he comes back and says "12 miles". That was enough distance for two airplanes to land before him. We turned base and landed. The other airplane took off behind us. We were parked and deplaned by the time the Execjet touched down. The lesson is, don't be afraid to speak up if you don't understand what the other guy is saying, even if it is a jet traffic.