Robin Gibb has not been able to speak for a week.
The Bee Gees singer is still battling colon cancer in hospital, and is only able to communicate by blinking his eyes, as he has a tracheotomy tube in his neck.
His wife Dwina and grown up sons Robin-John and Spencer remain at his bedside, and he is regularly visited by his showbiz friends.
Singer and close friend Jim Dooley told the Daily Telegraph newspaper: "He can't speak at the moment because he has a tracheotomy, and he has to communicate by blinking his eyes.
"Dwina has said that because he spent so long in a coma there are a lot of things he will have to learn to do again if he comes through it.
"He will have to re-learn how to walk. It's 50/50 whether he comes through this but Dwina is a wonderful woman and is giving him all the love you can give."
Robin, 62, has contracted pneumonia, but came out of a coma after 12 days last month, astounding doctors with his recovery.
Chemotherapy for his condition is on hold while he regains strength.
Dr. Andrew Thillainayagam of Imperial College London has paid tribute to the 'Night Fever' singer's strength and resolve in his battle against cancer.
He said: "It is testament to Robin's extraordinary courage, iron will and deep reserves of physical strength that he has overcome quite incredible odds."
However, he did warn that when he awoke from his coma, Robin was "exhausted, extremely weak and malnourished."