This happened to me when was about 5 or 6 years of age. I live in Petaling Jaya / Kuala Lumpur, Malaysia, and it was a Sunday morning. Usually, my whole family wakes up late on Sundays (as most people do) and start making pancakes at about 10.30 or 11 am. I have 3 sisters, Marena, Anna and Natalie, and I share a room with Natalie, whereas the other two share a room together.
Anyway, that particular Sunday morning, I woke up to go and pee, it was early about 6 to 6.30 in the morning, which is early for a Sunday. When I returned to my bedroom in a relieved but quite sleepy state, I looked over at Natalie's bed and she wasn't there! At least, I didn't SEE her (being quite sleepy). So I asked myself aloud, "Where's Natalie?" Suddenly an adults voice replied, "She's asleep." I checked her bed again, pulled the quilt off, and sure enough she was still sound asleep. But that's not the scary part. The scary part is, who was that who answered me? I thought it was my dad but upon checking my parents bedroom, I found that they were both sound asleep. The voice had been quite gentle, though.
This is completely up to you to believe, but I swear it's true.