In 1927, The Jazz Singer hit screens in the US. It was the first feature-length film with recorded dialogue. Since then, screenwriters and directors have struggled with how to use dialogue most effectively to contribute to movie storytelling.
Jack Nugent, a critic who previously showed us how movie trailers are designed, brings us this analysis of dialogue in movies. The best expository dialogue (dialogue which explains something to the audience) passes what Nugent calls the Dead Parent Test. If the story opens with a parent already dead, it's necessary to tell the audience. But the way in which that death is mentioned shouldn't seem obvious and forced.
Nugent demonstrates effective and ineffective dialogue with The Karate Kid, Pulp Fiction, Juno, Titanic, and other movies.
Content warning: NSFW language.