Know your audience.
When I sit down to write anything, I always have a target audience in mind. If I’m working on a YA novel, I’m thinking of teenagers between the ages of about 14 and 19. When I’m working on children’s picture books, I’m usually envisioning my own kids at ages 5 and 7. When I was in school and working on an essay or paper, I had my professor and classmates in mind. And when I wrote Homework Helpers: Essays and Term Papers, I had an audience of frustrated students who had to write a paper in mind.
If you know your audience, you can gear your book or project for them. And I'm not talking about writing for trends or trying to force your books to be what someone else wants them to be. I'm talking about knowing who you are writing for. Who is going to be reading your book?
If you know this, you can keep the writing, and the language specifically, appropriate. Now, I’m not talking about swearing or questionable jokes or anything. I mean using the big, field-specific technical language in your papers where your professor will appreciate them and keeping your young adult novels teen-friendly by using the type of language teens use when they speak; using kid-friendly words and terms in picture books; keeping the aliens in their sci-fi worlds and adding the hot and heavy sex scenes to the romance novels, but maybe keeping them out of a NF textbook :D
Can they blend a bit? Sure. I love a little overlap. I love a touch of romance in my sci-fi novels (or any novel really) :D I love a little supernatural in a good mystery. I love a hint of maturity in a cute MG. And maybe a bit of playful youthfulness in an adult novel. It can be hilarious to see an adult talking like a kid or a really smart kid sound more adult than the adults. Nothing is absolute and it certainly doesn't need to be when writing.
But think about it. How popular is your YA novel going to be if you use so many huge, unreadable words that your readers have to run it through a translator just to figure out what you are saying? How popular will your adult spy thriller be if your main character is a bunny named Buttons who solves crimes with his sidekick Terry Turtle? (Although that would be a totally cute PB! Might have to get on that....) What kind of grade are you going to get if you turn in that college-level essay peppered with phrases like “So, dude, like you should totally just listen to me cause I like tooootally get what I’m doing.” ?
No matter what you are writing, you’ve got to keep your audience in mind. I guarantee they’ll love you for it :)
Do you keep your audience in mind when you write?