Robert Kennedy Jr.s voice has become raspy due to a rare neurological disorder called spasmodic dysphonia. He was diagnosed with this disorder around 1996, and one of its symptoms is a raspy voice. In a recent interview, he stated that he had a very strong voice until he was 42 years old, but an injury in 1996 caused the neurological disorder. Despite his condition, he has stated that his voice is getting stronger.