Another question: I can do my own voice, or a child’s voice. That’s it. I have no idea how to figure out how another character would speak, especially someone who has a big speaking part. How do you improve at this? Is there a way to research
I try to put myself in the character's head. One thing that helped me to get better at it and, bear with me here, was playing tabletop RPGs like Dungeons and Dragons. Instead of making bespoke characters for them, I just take my own characters and "reskin" them for D&D. You'd be surprised how well you can develop a character when you get thrown into situations where they, and you, have to think quickly! It works wonders for getting to know a character if you have to roleplay as them for months to even years at a time!