With the common practice nowadays with CS:GO servers having deadtalk disabled so that players are able to communicate with the other dead members of their team. This is useful because it means that teammates that are still alive will not be distracted by the other members of the team.
Similar to how ESEA has it setup, during the first 5 seconds after a player’s death, they will be able to talk to alive teammates. After this period, the user will be muted and will only be able to communicate with dead teammates.