Well, Malte, that was a typo indeed.
Okay, here's the actual truth guys.
The answer is... FACT!
I know what you're saying. I too searched endlessly for a webpage that had such information, and found none. Also, as far as I know, there is NO book that exists that proves this information. The ONLY thing that has this proff is a little 2 minute video showing multiple pictures of him, with his own voice rerecorded right into it. Which was his own testimony on Joseph Smith and the Latter-Day Saint Church.
He used, what he called, "a talking machine."

Such simplicity. He didn't even know the name for it, and yet, he figured out some way, quite quickly, to make us understand what he was using.
Trust me, I didn't even plan this one. I just knew the answer without having to look up all the information. Let's just say I'm as surprised as you guys are. :^.^:
If you must know the WHEN, it was the last year of his life, age 91. Before the illness that killed him took over. I don't have an exact date of when it was recorded, but it was indeed within the last year of his life.
He was indeed the first Latter-Day Saint Prophet to record his own voice. Though there is only one piece of information that proves this, it is enough in the end.
Since no one could guess it right. The next one is a free for all.
ANYONE can post a Fact or Crap! statement.
Though remember, only the FIRST one posted will count.