Here's one of the three-minute sound films produced by Deutsch Bioskop from 1906 through 1910. It's a brief excerpt from THE MERRY WIDOW, in which the chorus of the Moulin Rouge does a very sedate -- for that venue -- dance.
The copy I viewed showed some nitrate damage, and the sound was not of the quality that would impress a modern audience, but we're talking about something that was produced more than a century ago and twenty years before Hollywood began to produce talkies on a regular basis, so its primitive nature can certainly be understood. The field of action is constricted, because moving the sound equipment and the camera was just about impossible in that period. If you look at the sound shorts that accompanied the premiere of DON JUAN in 1926, you'll see that the camera sat like a lump of lead there too.
As a result this piece is mostly interesting as a piece of forgotten history. As that, though, it's fascinating.