A twelve year old will usually use the insult of "fag" or "bitch" while playing an online game, Due to a lack of thought to come up with anything original. see Runescape or Counter Strike.
This is also the age where most mall goths are born. When approaching teen years an individual will be looking for an identity. Also they will develop a sense of rebellion. Thus adopting the mall goth subculture. Seeing as how it is rather frightening and exotic when one first examines somone clad in make up and fishnet. But as the 12 year old gets older hopefully they will realise how silly it is.
The 12 year old male will usually talk alot of shit. Because he is so close to his teen years and little pubes are starting to sprout he feels the need to be a man. Which usually results in the 12 year old getting his shit ruined.
The 12 year female will have a tendency to dress more revealing or slutty due to her body developing. She feels the need to show it off like the pop stars on TV. This is where most fights with the parents start in.
kid2: wow you cursed you must be really cool
teenager: they must be like 12