Some say the French say it that way, though I have no idea what evidence there is for that. I do know Kerry disputed that someone wrote his speech for him but Robert Kennedy's speechwriter did write it. I always thought the pronuncation was due to that.
At any rate, it is chilling to learn that one of the POWS that was taunted with the recording of Kerry's words while he was held prisoner recognized Kerry just this year when he once again heard the audio and that pronunciation. That was his clue that it was Kerry whose voice he had heard. He said when he heard "Jenjis Kahn" the hair on the back of his neck stood up and he finally knew.
That is one of the most moving stories, cyncooper; I heard him on the radio the other day and it gave me chills.