Show people have a saying that the movies are pictures with sound, while TV is sound with pictures. Historically this has some truth. The movies were silent for their first three decades. They only added sound in 1927. Meanwhile, the very first TV shows, in the late 1940s, were little more than radio shows with a fuzzy black and white picture. The TV networks were radio networks that added TV stations.
What are the conclusions we can draw from this bit of history?
None, as far as I'm concerned. In the motion picture medium, sound is not some poor cousin to picture, no matter what French critics say. When producers overrun their budget and skimp on the sound, it can destroy the movie however nice the visuals are. Likewise, dialogue is not the red-headed bastard stepchild of action. Dramas lend themselves to dialogue scenes; action movies to scenes of actors running, jumping and falling down. Telling a story through spoken words is not, per se, inferior to telling it through images.
In his book Screenwriting Tricks of the Trade, screenwriter Bill Froug suggests that, as an exercise, before you write a scene, you try to imagine how you would write it if you were making a silent movie. Sometimes a single visual moment can show more than pages of dialogue. There's a story that Frank Capra hired a famous playwright to write a screenplay. After a few months, he checked in. The famous playwright had written two beautiful reels of dialogue, twenty pages that showed a marriage that had once been strong but was now fading.
Capra's response was, "Here's what we'll do. We show the husband and the wife in an elevator. The husband has his hat on. Elevator stops. A pretty girl gets into the elevator. The husband takes his hat off for the pretty girl."
Any time you can communicate the essence of twenty pages of dialogue in one scene (and better yet, one shot in an elevator!), go for it. Any time you can come up with a completely new way to write any scene, it's worth trying. Then you have two versions to choose from.
The corollary to Bill Froug's idea is that any time you have a scene of pure action, you should probably also try to think of how you could replace the scene with dialogue. For example, in Blade Runner, Rick Deckard's old boss menaces him, "You know the rules, pal. If you're not cop, you're little people." That single line carries more threat than an entire scene of, say, Deckard getting stalked by thugs.
Dialogue is soft; it is filtered through our understanding of language. Images are hard. We absorb them without having to put them into words. Dialogue can give us more factual information, but if you really want us to know one thing, show it to us. The audience may entirely forget a line about an ice pick, but they won't forget a closeup of an ice pick under the bed.
You can use the relative softness of dialogue to filter scenes that would otherwise be too harsh to put on screen. In Jaws, Quint (Robert Shaw), the shark hunter, tells a story about the sinking of a US cruiser in World War II. The actor conjures up the screams of the sailors as sharks tore them to bits in the water. There's no way we'd want to see that on screen, even if you could afford to shoot it.
You should also use dialogue when what's important is how the character feels about an event, not the brute facts of the event itself. If part of your story is that a woman is raped, you may well not want to put the rape scene on screen. Not only will the scene blow the rest of the movie out of the water, it may not be so important exactly how it happened. What's important is what she feels about it.
In A Fistful of Dollars, the Man With No Name rescues a family. The father asks the Man With No Name why he's risked his life for them. The Man With No Name rasps out, "Because once there was a family like yours ... and there was no one to help." We don't need to see what happened to the Man With No Name's family; we only need to know how he feels about it.
Images are very good at telling us what. Words are very good at telling us why. A story can't exist without what, but it won't make any sense, and we won't care, without why. That's why two years after The Jazz Singer introduced talking pictures, no one in Hollywood was making silent films anymore...