The voice of Alexander Graham Bell has been identified for the first time, in a recording from 1885.
On the wax-disc recording, the telephone inventor says: "Hear my voice, Alexander Graham Bell."
The recording is among the earliest held by the Smithsonian Institution, which runs the National Museum of American History.
Bell's voice was recorded on to the disc on 15 April 1885 at his Volta laboratory in Washington.
As well as saying his name, he also recites a series of numbers and lines from several Shakespeare plays. The sound clip has been posted online.
"Identifying the voice of Alexander Graham Bell, the man who brought us everyone else's voice, is a major moment in the study of history," said museum director John Gray.
"It enriches what we know about the late 1800s, who spoke, what they said and how they said it."
The disc was too fragile to play using a needle so the museum, along with researchers at the US Library of Congress and the Lawrence Berkeley National Laboratory, developed an alternative play-back system that used light and a 3D camera to turn its bumps and grooves into sounds.
Also identified was the voice of Alexander Melville Bell, the inventor's father, in a recording from 1881.