silent

This is certainly the last "silent" film that I have seen. I found it interesting to note a some vocalized groaning by Allan Fields while he was hidden out in the apartment down hall from Rita Gam's character.

Also, about 34 minutes into the film, one of the female spies vocalized a throaty yell when she was shocked to find that her co-conspirator had been hit by a car.

I thought it was funny that the phone was allowed to ring without being answered. Of course, that would have meant talking. Also, I got the idea that Fields was counting the rings as a signal to him from his fellow agents. However, this would be a very unreliable signal because one could never be sure when someone else in the apartment would answer the phone.

As a man thinketh in his heart, so is he. - Proverbs 23:7

Mel Brooks 1976 Silent Movie comes close.

Reality leaves a lot to the imagination. ~ John Lennon

"Tribe" (2014) a Ukrainian film is a silent film which the only dialog is in Ukrainian sign language. Of course there are natural sounds like tree branches swinging in the wind and the passing of a bus