The guy that discovered it BSs for a few minutes before the actual truly weird footage begins.
Caught on early silent film.
You need to watch the VIDEO all the way to the end because that is where the Zoom In and the radically slowed and stopped footage is located.
The person is obviously talking into some hand held device that he/she is clutching up to the ear.
There was no cell phone in 1920, or walkie-talkies or any mobile communication devices in fact they were not even dreamed of back then.
Then also check out "her" strange shoes in the slowed down footage.
I don't think that shoe style existed in 1920 either.