It depends on the character. No two kids are going to act the same obviously. Every kid has a different maturity level and the class bully isn't going to react to things the same way the class clown is.
I guess in general though... don't play them too young. You are playing a preteen, not a toddler. I have seen far too many people play 10-12 year olds like they're in the 4-6 year range. A preteen is usually not going to be doing baby talk or overly cutesy shit unless their doing it on purpose. Maybe they mispronounce or misuse words they are unfamiliar with, but that's only on occasion.
This is also a time when kids start noticing the opposite sex and exploring sexuality. I'm not talking about makeout or other more intense stuff. But you know, like schoolyard crushes or an eleven year old girl putting up pictures of Justin Bieber because she thinks he's cute and she wants to marry him.
My best advice, watch some shows with kids in them and see how they're portrayed. I'm not talking about a show made for kids, I'm talking about an actual adult show, like a drama or even a sitcom that isn't too wacky. Find a few episodes that feature kids prominently and see how they're portrayed.
Re: Child Characters
I guess in general though... don't play them too young. You are playing a preteen, not a toddler. I have seen far too many people play 10-12 year olds like they're in the 4-6 year range. A preteen is usually not going to be doing baby talk or overly cutesy shit unless their doing it on purpose. Maybe they mispronounce or misuse words they are unfamiliar with, but that's only on occasion.
This is also a time when kids start noticing the opposite sex and exploring sexuality. I'm not talking about makeout or other more intense stuff. But you know, like schoolyard crushes or an eleven year old girl putting up pictures of Justin Bieber because she thinks he's cute and she wants to marry him.
My best advice, watch some shows with kids in them and see how they're portrayed. I'm not talking about a show made for kids, I'm talking about an actual adult show, like a drama or even a sitcom that isn't too wacky. Find a few episodes that feature kids prominently and see how they're portrayed.