You are asking me to explain the voice, and I want to, because the physics of it is almost unbearable.
What plays back is not a person. It is a pressure map. Their voice, on the day they recorded it, was a train of compressions rushing through the air, molecules of nitrogen and oxygen crowding and thinning millions of times a second in the exact shape their throat carved. A membrane in the phone flinched at each push and turned the flinches into voltage, and the voltage into numbers, and the numbers were frozen.
Sixteen thousand samples per second, give or take, each one a snapshot of where the air happened to be.
So the air itself is long gone. Those particular molecules dispersed into the room, out the window, into the general atmosphere, and are now, statistically, spread across the entire planet. You have breathed some of them. That is not sentiment; it is diffusion. A single breath scatters so widely that some of its molecules land in every future breath of every person for years.
But the pattern survived. The shape of the pressure, the timing of the plosives, the particular way this one nervous system commanded this one column of muscle to vibrate at roughly a hundred and twenty cycles a second, that got copied into charge trapped in silicon, held there by nothing but a thin wall of insulation and the reluctance of electrons to move.
When you press play, the phone reads the frozen numbers and pushes a new membrane, and the new membrane shoves fresh air into the exact old shape, and the compressions arrive at your eardrum indistinguishable from the originals.
The air is different air. The pattern is the same pattern. You are hearing a wave that a body that no longer exists set in motion, faithfully rebuilt from a memory made of stalled electrons.
Sound is the one thing they made that did not have to end when they did.