Me too! Ive noticed this a lot more lately. I have a best friend and when I talk to him he instantly he yawns then laughs about it. Yet Ive just spent the last year helping him with his life situation which was non-stop counseling type scenarios. But now that he's on track and life is good I can finally let a few things off my chest and BOOM the yawning begins. wtf...? My husband also does it as soon as I talk about stuff I do. I talk fast to 'get it out quickly' but nope, here comes the yawn. Last night I spoke with a lady friend at work. We even talked about awesome stuff....YAWN. What you said is exactly how I feel too, I was hoping maybe my voice is soothing and theyre relaxed but I end up doubting that.