It is not fully understood how much a person in a coma can hear or understand, as it can vary greatly depending on the individual and the cause of their coma.
Some studies have suggested that some people in a coma may be able to hear and respond to sounds and voices around them, while others may not. It is also possible that some people in a coma may be able to hear but not be able to respond.
It is important to note that even though a person in a coma may not be able to respond to voices or sounds, talking to them and playing familiar music or other sounds can be a comforting and therapeutic for both the person in a coma and their family. In addition, the person in coma may be able to hear the voices of their loved ones and it is believed that it could have positive impact on their recovery.