Known as "The Man of 1000 Faces", Chaney signed a legal affidavit declaring all the voices he performed in this, his only talking film, were actually his own. Thus, in addition to multiple characters, he performed multiple voices.
The trivia item below may give away important plot points.
The original end of this movie was exactly the same as the silent version (with Echo returning to the sideshow and allowing Rosie go back to Hector). This version was filmed, but it was later decided to re-shoot the end with the conclusion that it now has (with Echo boarding a train for prison).