“The disease didn’t hit me until I was about 43,” Kennedy told Oprah Winfrey in an interview in 2007 widely cited as the first time he publicly discussed his disorder. At the time, he noted “it is an effort” to speak despite it not being physically painful.
Time progression videos of RFK Jr.’s public appearances show that his voice began to change in the late 1990s.
1973 Joseph P. Kennedy 2d, the son of Robert and Ethel, is the driver in a car accident on Cape Cod that leaves one passenger permanently paralyzed.
1984 David A. Kennedy, son of Robert, dies of a drug overdose in a Palm Beach, Florida, hotel. He was 28.
1997 Michael Kennedy, the son of Robert, dies in a skiing accident in Aspen, Colorado. He was 39. Prior to the accident, Michael made headlines for allegedly having a long-term affair with his children's babysitter.
1999 John F. Kennedy, Jr., his wife, Carolyn Bessette Kennedy, and his sister-in-law, Lauren Bessette, die when their plane crashes in the waters off Martha's Vineyard, Ma. Kennedy was flying the Piper Saratoga plane that plunged into the Atlantic Ocean.
2002 Michael Skakel, nephew of Ethel Kennedy, was found guilty in June by a Connecticut jury of the 1975 murder of Martha Moxley. Skakel was 15 when Moxley, also 15, was found bludgeoned to death outside her Greenwich, Conn., home. Skakel was sentenced to 20 years to life in prison in August.
(see article posted above by LRAD)
https://www.infoplease.com/history/us/timeline-of-kennedy-tragedies#1973
https://www.infoplease.com/history/us/timeline-of-kennedy-tragedies
So what is breaking or blocking the voice of RFK jr.? In my view fear! - Change my mind!