Dead players can hear and communicate to living players through direct chat before respawning.
Here is an example of this happening on Barely Infected's The Village. Please excuse the salty interaction. The dead player starts talking at 2:00. They look like they're uncon but they were dead.
There were at least 7 players in the area + 3 cars. The 5 on my side could all hear the dead person talking. I do not know if this happens every time.