Some unresponsive dying people still show brain responses to sound. That finding doesn't prove conscious awareness, recognition, or understanding. Since no one can determine the person's inner experience from the bedside, speaking gently can still be worthwhile.
The evidence is limited and the practical guidance is simple: talk to the person, identify yourself, keep the room respectful, and don’t promise that every word is being heard or understood. For the full picture of the final days, read what dying can look like.
