Ну вот на гизмодо нашли обяснение человеку с сотовым из фильма чаплина, а жаль.

via tv.gawker.com

Irish filmmaker George Clarke, the dude in the clip above who was really into the idea of the lady being a time traveler, apparently didn't talk to many hearing experts—a few have suggested that the object the lady is holding is likely an ear trumpet, essentially old-time analog hearing aid.