“Today I noticed my parrot has started making a strange sound when he sleeps, and when I feed him. I can also hear this sound in his voice while he is breathing. I am very worried!”
I have to begin this by stating that I am not a liscenced or practicing veterinarian and I cannot offer you any technical, legal, or medical advice.
I can give you my opinions, and some options/avenues to explore in order to find help.
That being said…Uh oh. It sounds like he has a respiratory problem–most likely an infection or injury to one (or more) of his lungs. Birds also have four air sacs inside their bodies, which are used to keep them light and air-born, as well as to help them breathe. Unfortunately, the air sacs commonly collapse. This usually occurs after inhaling pesticides, smoke, or other pollutants. It can also come from traumatic physical injury (even one we did not observe with the naked eye, as birds and their air sacs especially are fragile), or from inhaling water.
You need to take your bird to he vet as soon as possible. This is an emergency that must be treated immediately. If you do not take care of a lung infection or injury immediately in birds, the outcome is unfortunately very grim.