P easy when I have their behavior noted down!

Surprisingly difficult as I have to factor in their personality, the context and several headcanons in my head.

Honestly depends for me. It's better for me when a scenario is presented and I can work with, or a friend to bounce off of, but there moments of "I got nothing".

Considering Avian originally started out as a self-parody of my own worst aspects before he eventually became his own person, remarkably easy. I know exactly where to draw from for him.

Easy, if I have the right amount of information. Hard, if I have to o in blind. Basically, I need to know what I'm working with to construct proper dialogue. Otherwise, it can go south VERY quickly, especially if it makes my OCs look OOC.

Depends on the characters. Sadly I haven't been able to create much cause I kinda need some back-and-forth with people to generate that inspiration spark. Alas, not many people want to

For Odd, it can be a little difficult finding the exact wording for dramatic and/or introspective moments, but in most casual/neutral scenarios where he has his "articulate but weird" persona (I draw a lot from Brian David Gilbert for inspiration/delivery), I think I can make scripts that at least somewhat capture his voice.

Pretty easy I’d say. For Jin she speaks pretty proper and polite, but she has a tendency to be a bit corny when talking with Mary, she can’t help it haha.
And for Mary I try my best to convey her accent without actually writing it in with punctuation.

It depends. Sometimes I can think of dumb bits and spin something from them in head. But when it comes to putting pen to paper, I always get stuck making it feel human and genuine. I feel like I gotta talk to other people as I do it eventually, to get a more dynamic feeling.

Suprisingly easy!
I'll come up with lines/interactions I think are cool or funny at random and then write characters or story moments around them.
Half the time the first thing I'll share of a character to friends on discord is a dialogue interaction before I even have a design. Sometimes I turn those lines into comics (like the Sivrit one) or storyboards(Like the Darkrai one).