This is something that happened just recently. I was returing home late from hanging out with my friends. It was about 12:30 at night. As I drove up the driveway, I noticed that the lights in the lower half of our barn were on. This area is comprised of three stalls for our horses. Thinking my dad was out checking on our recently born foal, I walked out to investigate. Nobody was in the barn. I looked in, and for some resaon decided to say out-loud "Is there any particular reason that the lights are on" In case my dad was inside. I went in, looked, and, finding no one there, walked back out and turned off the light. The moment I turned out the light. I hear a male voice give a friendly chuckle.

I didn't hang around to investigate any further... I booked it back to the car
This is the only vocal phenomenon that I've personally experienced at my house.