This is a great article by Graham Moore, the Academy Award nominated screenwriter of ‘The Imitation Game’:
[A]fter our scientist has finished, the camera turns to a second character. This would be our scientist’s normal-dude buddy. He’s just a regular Joe. He is the audience’s stand-in during the scene, and the character with whom the audience most identifies. This guy makes an incredulous face in response to the scientist’s technical language. And then he says the following line:
“WHOA, Doc. Say that again in English!”
You know exactly what I’m talking about. You’ve seen this moment on screen, you’ve seen it on TV, you’ve read it in novels. I find this moment to be extremely condescending to its audience. The moment essentially signals to the viewer that all of that mumbo-jumbo that this smarty pants has been blathering on about, well, we filmmakers do not understand a word of it. Moreover, we don’t care to. And we have no interest in your understanding it either.
Graham walks through how he avoided this in his screenplay about genius mathematicians, with examples from Arthur Conan Doyle’s Sherlock Holmes works. It’s clever, you’ll recognise it, and it doesn’t condescend to your audience.