The concept of sound didn't exist until roughly the 1870s, when the gramophone was invented. -- RecklessPrudence
"A listening engine?" Clara repeated.
"To aid the deaf, I initially thought. Something to translate the noises we make into a visual medium, and thereby aid understanding. Of course, its spelling would be atrocious, but the message should get through." Montague tweaked his latest contraption. There was an ear trumpet, and a progression of springs, and a pencil balanced carefully against a roll of paper. "So far, I've been analysing the vibrations of the human voice. Watch."
He wound the machine up and pressed a switch. Then recited, "You look wonderful, today, my dearest Clara," into the trumpet. Things jiggled. The pencil moved as if it were possessed. It all stopped again when Montague flipped the switch the other way.