I could go on and on and on about this, but I'll try to be brief: my DD is 6, in the middle of kindergarten at a wonderful literature magnet school in our neighborhood, going to aftercare for a few hours every day.
She's always shown a little sass, but lately it's taken off. Eye-rolling, huffing, stomping, "what-EVER" ing, talking back, clamming up, arguing, picking at every. little. thing. I feel like she's an adolescent and I am not ready for that. :)
She doesn't watch television, so I don't think she's picking it up there, though on occasion when we are visiting out of state family she will watch some of the awful kid-coms that are rife with attitude. There are a few 10-ish year old kids in her aftercare that probably lend some examples.
Regardless of where it's coming from, I don't know what to do about it. We usually just ask her to "try again," and give her a second chance to not be so abrasive. When that doesn't work, we send her to her room until she's ready to come out and speak kindly and respectfully to the rest of the family (me, DH, and 2YO DD).
I don't want to completely restrict her speech and expression-- we all get pissed off, me included. But I'm at a loss when it comes to teaching her the difference between being a jerk and being irritated. Sometimes I don't think she even IS irritated, I think she's just pushing buttons & boundaries.
She's always been really great at talking about her feelings-- telling us when she feels embarrassed, hurt, or shy. It's the huffing and shutting down that's got me rattled. And it's hard not to bristle and respond angrily myself, which I realize just gives her a reaction which is probably what she's looking for.
Does this happen in your house?