I love so-called "silent films." They aren't really silent, of course, because they are always accompanied by a musical soundtrack.
I am never discouraged, disappointed, or frustrated by a silent film. Anything I can't hear is supplied by the visuals or my imagination or the musical accompaniment. When I remember a silent film, I remember the dialog as if I heard it spoken. I interact with the film because I concentrate and use my imagination. It's like I'm reading the movie. I get taken up into the world of the film.
Everyone today was born in the film era. We don't know what it's like to live in a world without moving pictures. Films are history lessons. They are a window on the world of my grandparents' childhood. That amazes me.
They used to say these things about books. That books allow you to travel through space and time in your imagination. Silent films are a hybrid of book and film.
If you're worried about TV damaging your kid's learning ability, make him watch silent films. My niece loves them.