If it's a formal name then the pronounciation could be almost anything. If I had to guess I'd say it might be "yorger"? or maybe "ERGER"? I'd suggest asking him/her to rponounce it slowly for you a few times...
I am too a ioerger from illinois and i heard that it's a scandinavian name, in fact a person educated with the swedish language would no the exact pronounciation in a heartbeat. I've also heard we have german heritage due to the invasions of europe in the past. Either way it's "yager". German word for yager meaning hunter is Jaeger. And my sub in german knew swedish and she asked if my last
Ioerger is pronounced" yeager" . The origin of Ioerger ancestors with the" I "spelling are said to have come from Alsace Lorraine region and a mix of german and french.