This is from all the posters in his gang's hideout, which are heavily implied to be written by him.

It's actually so awkward and simplistic that I understand why it's commonly thought in fandom that English wasn't his first language. All of these are written in an incredibly choppy way, with short sentences and lots of "yelling" (allcaps/exclamation points).

I wonder if this is just how he wrote notes and posters, or if this is actually how he spoke, as well.

I don't think there's any evidence that Joy usage normally does anything to your speaking style unless you're directly in the process of mutating, so...

Also there's this guy here who implies that Dice referred to orders/directions given to his men as "chores" which is, just hilarious. Or he dished out ACTUAL chores...