There are levels in YA. Some are oriented towards the younger group (say 11-14) and others are oriented towards to older teens. For example, I think the Hunger Games books were more oriented towards the older teens. I've seen some YA that I would classify as light romance novels, that I suspect are oriented towards older teenage girls.
I think that some of what makes YA, is a combination of vocabulary and most things are a bit more straight forward and direct. You don't see the narration jump around quite as much. Things aren't as subtle in a large part because kids don't tend to pick up subtlety nearly as well as adults do.
|