For filmmakers and script writers, here’s practical dialogue advice from screenplay expert Michael Ferris:
Keep your film dialogue short.
“A script is not a play – your goal is NOT to have dialogue that looks like a bunch of monologues. Try to keep 95% of your dialogue to 3 lines or less on the page. Clever dialogue is found in quick back and forth exchanges, not prose-y speeches. Think about one of the best screenwriters known for his dialogue – Aaron Sorkin. Have you ever watched a scene from The West Wing? It’s not a perfect example, but it illustrates the point that if you keep it snappy, it keeps it moving. And a fast moving script, like a fast moving story, is entertaining and – sometimes – it can move so fast that you don’t have time to realize whether it’s great quality or not. You just know you’re entertained. So, use it to your advantage. Keep the dialogue short, quick back and forths, and you’ll reveal plot and character just as quickly.”
The quote is from my ebook, Filmmaking Basics: Finding Your Creative Voice.