Real people don’t have scripts to read from.
But seriously, listen to the way people talk. It’s chaotic, messy, often unclear and very inefficient. Conversations meander wildly, with dangling threads that are never concluded and often times with people talking past each other as much as to each other. If you wrote dialogue that way it would just be harder for audiences to follow and waste precious screentime.
Realistic sounding dialogue is about writing what a real person would say if they stopped to think for a minute between each statement.
Which is why Steven Spielberg’s early movies were so refreshing. The overlapping dialogue of his various breakfast/dinner table scenes were a standout of his style.
Scripted dialog is usually idealized, not realistic. Whenever a script includes someone getting tongue tied, it’s always to say something about them. There are characters that do often mess up words in a script, like the nervous young person with a massive crush or the constantly distracted old genius
That’s why one take Jake gets paid the big bucks.
I like a lot of stuff Aaron Sorkin does (The West Wing, for example, but also The Newsroom) but damn, his dialogue is too perfect. Nobody talks that way IRL.
