I've been working on a screenplay with my wife, tentatively titled Figment. It's about an illusionist who takes his dead rival's daughter as his apprentice. We're almost done with the first draft, and it's been a novel experience in a couple ways I thought were worth writing about.
First, this is the first thing I've written with a partner, and it's the first time my wife has officially done any writing. I've been trying to convince her to give it a shot sometime because of how big a role she has in my writing anyway; I told her, she doesn't have to do half the work, just a little bit more than she was doing already, and she'd deserve a spot on the cover page.
So I am doing most of the work, especially on the first draft. We talked out the outline together a lot, and now I've been doing the actual writing, while we discuss what I've written occasionally. The plan is for her to take a larger role in the editing; it'll basically still be a lot like my solo process, but I'll take specific tasks and pass them off to her. For example, if I have a character whose behavior is inconsistent, we might have her go through and polish that character's dialogue.
It's the first time we're trying it and her first time writing, so we're kind of expecting the final workload to be roughly 80/20, but if it works out and she enjoys it, future screenplays might wind up somewhere between that and 60/40.
The other thing different about this screenplay was lack of a structured outline. I normally like to have a pretty strong skeleton before I start writing, so that I know exactly what I'm gonna write before I write it. I rarely end up following the plan to the letter, but having it there at least gives me an idea of how much I'm deviating from the plan.
This time, though, we had more of what I'm calling an "emotional outline." We knew how we wanted it to feel all the way through, had a few scenes we wanted to get to as guideposts, but otherwise we actually overlapped the outlining with the writing a lot more than I'm normally comfortable with.
So, for example, I'd write a dozen pages, we'd read them together, talk about if they hit the notes we wanted, and if they were getting us where we wanted to go. We'd talk about what should probably come next, then I'd go write those dozen pages and we'd reconvene.
It's a lot more seat-of-my-pants than I'm used to, and to be honest, I don't love it. I think it was probably the right choice for our first time working together - I think she was more comfortable with this process than making a solid outline - but it's actually driven me to outline even harder for my solo stuff.
I'm excited for the prospect of finishing this screenplay with my wife, want to do more with her in the future, but I'm a pretty solitary writer on the whole, so I don't think I'll ever transition to doing literally everything with her.