my biggest problem in my own particular fandom is that most of the POCs are actually foreign, and i don't know their first language well enough to know how their english speech patterns would work. i can write a fair phonetic accent, but the only language i know well enough to simulate an ESL speech pattern for is french, and that's no help. and if you mess something like that up, you just make the person sound like an idiot manchild, which is pretty horrifically offensive. unique situation, but that's my struggle.