Lydia Jones, a spokeswoman for BAFTA Cymru, said Friday that the organization had been told there would be no further details on Mr. Jones’s condition. Primary progressive aphasia is a rare nervous system syndrome that affects a person’s ability to express his or her thoughts and understanding, or to find words, according to the Mayo Clinic. Symptoms begin gradually, often before age 65, and worsen over time. The news of the diagnosis was also reported by the BBC and Britain’sNational Press Association. The announcement of Mr. Jones’s illness dominated Monty Python fan siteson Friday, where it was described as “sad” and “terrible” news. Eric Idle, a co-founder of the ribald, outrageous and internationally acclaimed British troupe, tweeted thanks to fans for their support while noting Mr.