We can now hear, across a gulf of 140 years, some silly noises and a count to six, one of the earliest audio recordings.
Until recently, the oldest recorded sounds of known date which anyone could hear had been captured in 1888 on the "perfected" phonograph introduced that year by Thomas Edison. But Edison had invented his original phonograph eleven years before that, in 1877--and recorded sound itself is even older: In the 1850s, Édouard-Léon Scott de Martinville of Paris created the phonautograph, an instrument which scratched records of aerial sound waves on soot-blackened paper, not for playback, but for visual study. This means there is a big disparity between when sound was first recorded (around 1857) and the earliest recorded sounds we could actually listen to (1888).
That changed in 2008 when FirstSounds.org released a sound file created from a phonautogram of "Au Clair de la Lune" as sung on April 9, 1860. Suddenly we could hear more distantly into the past than ever before.
Even so, the intervening history of recorded sound -- including the transformation by American inventors of the phonautograph into a "talking machine" -- has remained frustratingly silent. The indented tinfoil sheets produced by Edison's exhibition phonographs of 1877-78 weren't regarded as permanently playable recordings, and little care was taken to preserve them in a playable state. No intelligible sound recovered from a historical tinfoil recording has ever been published.