Aldenard said:
From what I have read, it seems to be best to only allow characters to say what is relevant and important to the plot or perhaps character development. So in writing a segment of a screenplay, I noticed I had an incredibly long period (10-15 pages) without a single scrap of diologue. Should I change the pacing perhaps? Some screenplays, such as Cast Away, seem to have the protagonist speak for no other reason than to state the obvious and so that there exists dialogue, even flimsy. Is unnecessary dialogue sometimes good to lighten the mood or pace the film better?
In "Cast Away" Hanks' dialogue expressed his inner thoughts, better than using voiced over narration and fitting because people who are lost and isolated are known to speak just so they can hear a human voice. I think if you reviewed his speeches you'd find they contribute to the advancement of the story, one way or another but probably to reveal his advancing state of mind.
I've not ever faced the situation you face so it's a hard call, except to say that 10-15 pages sans any dialogue at all is probably not going to fly.
So, either recrank the sequence in some fashion to get a scene or two or three into it that have dialogue, yunno, scenes you CUT TO: for a moment ot two, then CUT BACK TO: your sequence. Surely there's something else going on somewhere you could go to briefly. Or find a way to squeeze some meaningful dialogue into the pages you have, even voiced over narration might work.
But generally any dialogue you add should fullfill the function of advancing the story as opposed to being just some kind of meaningless fluff or filler, keeping in mind that anything is possible. Think about information you might have wished you could have conveyed somewhere along the line but never found a place to do it so didn't. Lay that information over your sequence as narration. It wouldn't necessarily have to relate specifically to the imagery and could almost be an aside, your protag thinking, remembering, or speculating, but conveying information that will help flesh out the story for your audience.
Again, a hard call from this distance.
Good luck!