Charlie Chaplin's Modern Times is a throwback to the silent movies of old, made at a time when the death of the silent movie was relatively new. There is talking, but you only hear words through technology - radios, records, telecommunication systems. Otherwise, the dialogue is conveyed through silent movie-style interstitials, or is gibberish. Chaplin felt the addition of sound to movies was basically pointless, but by 1936 it was pretty clear that it wasn't going away. But the fact that it had become a necessary part of movies didn't mean that Chaplin had to like it. So Chaplin made a movie that just wanted to be a silent film, but that technology kept forcing in all these spoken words.
And this idea ties nicely into the overall point of the film. The film is about how the overindustrialised and over-technologised world of 1936 destroys people's humanity and turns them into soulless robots. If it wasn't for the advancing technology, all these people would be able to be happy and free - and if it wasn't for the advancing film technology, Chaplin would have been able to make the film a silent, like he so clearly desired.
The problem with all this "technology - bad" moralising is that it doesn't really make sense in the context of the rest of Chaplin's filmography. I mean, in this film, the past is presented as some sort of pre-industrialised wonderland, where if you want some milk, you just went outside and got it straight from the cow. But this view of the past doesn't really make sense if you think about it in terms of Chaplin's films from that "pre-industrialised wonderland". His characters in those films are just as miserable and lonely as the characters in Modern Times. The only real difference is that those characters didn't have technology to blame their unhappiness on.
This problem is illustrated perfectly by the ending of Modern Times. Chaplin's films from the era Chaplin is yearning for always ended unhappily - the Little Tramp would have lost the girl, and would end the film wandering unhappily into the sunset, sad and pathetic and hungry. But in Modern Times, the film ends happily - by spurning the technological world, the Little Tramp manages to win the girl, and wanders into the sunset holding hands with his love and smiling. But if technology was the problem (as it so clearly was in Modern Times) then why weren't his previous protagonists happy and contented? If all one needs is a technology free world, then why are his characters who live in a technology free world intrinsically unhappy?
None of this is to say that the film is bad. It isn't. It's actually pretty damn good - almost as good as The Gold Rush. The ending, with its sweet and happy tone, is actually better than the usual Chaplin ending. Both types of ending are over-sentimental tripe, but with most of the endings, Chaplin seems to be punishing his audience for laughing: "Oh, you thought that was funny, did you? Well here's a downer ending, so you don't leave the cinema feeling happy. I mean, what is this, a comedy?" But at the end of Modern Times you actually do feel happy. But the fact that I liked the movie doesn't mean that I have to like the message of the movie.