The woman is passing in front of the camera holding her hand to the side of her face while talkin - similar to the way we talk into our cell phones. He therefore came to the conclusion that the woman is a time traveler. More sensible people came to a different conclusion: the woman is using her hearing aid (invented by Siemens in 1924).
It’s quite easy to understand why the woman cannot be a time traveler:
- If she would be a bona fide time traveler, she would not be in a Charlie Chaplin movie using a high-tech device. The idea is to remain incognito.
- Considering that you need cells and masts to get cell phone coverage - how was she able to get a connection? Or was she talking to the Indian helpdesk of Verizon?
- More intriguingly, with whom did she talk? “Hi, it’s your Mum. I am an extra in a Charlie Chaplin movie. Don’t forget to brush your teeth before going to sleep.”
Well, unless you are traveling with Doctor Who in the Tardis, you cannot talk on you cell across time (or space).
Mr. Clarke and his "theory" did create a viral storm on Internet, so at least he had his nanosecond of fame. Not bad for an unknown filmmaker....