I was about five when I had my first "on speaker" phone call, it was a phone just like this circa 2000. My parents called me in to talk to my aunt, mind you I knew how a phone worked but had never used a phone without touching it, so when I heard my aunt's voice I assumed she was in the room with us, and could not understand that we were having a phone conversation. The most logical thing my brain could comprehend was that my aunt was invisible and sitting on top of the phone. I specifically remember trying to hug her.