My 7 year old is a wise ass

I feel like I'm being outsmarted by a 7 year old boy. He's been a 50/50 custody kid for the last 3 years or so, along with 5 year old brother. These boys are bilingual, I am not. When 7 year old gets in trouble he often starts speaking to me/answering me in French (or sometimes in Italian which is weird because nobody has taught him Italian, he has language apps that he seems to be jumping around in). And he thinks this is hilarious. I don't have a clue what he's saying, I know what merde means and I know he's being a little merde but I don't get far past that. And he can really drag this out, like a diversion tactic. I don't know if I should be reacting to this or just ignoring it?This kid also loves to wind us up, he does this to his mother too. For example he won't cooperate, and he won't cooperate and he won't cooperate and then when you start getting mad about it then he says "haaaaa chill out" and again, thinks it's hilarious and then happily goes off to do what you wanted him to do 10 minutes ago while you're left behind in this bad mood. But then the thing with this pattern is that sometimes he actually is being defiant but both versions look the same at the start. So again, I don't know if I'm feeding this too much?7 and 5 are also big on roughhousing, which is fine. But then 7 goes on to do additional "punching bag" stuff and he likes to do it out in public. Like in the space of a few minutes today he ran 5 into a wall and then he did this crouch and stick his leg out while 5 was looking the other way so 5 then tripped over, flat on his face. Both times 5's first response was "ouch" but then he also finds it hilarious, so they're both finding this hilarious, and this old lady is looking at me like they're nutcases, which they are. After the foot trip I told 7, you're going to hurt him, stop it. I don't know what other discipline I can give walking down the street. Sometimes I feel like I need to constantly shadow 7 so that 5 doesn't lose his teeth. And when I mentioned that to wise ass he said "he gets new teeth though". Ok, well he needs the baby teeth for now doesn't he.7 is usually fine at school, if there's a complaint it's usually that he talks too much and doesn't shut up. When you question him about that he tells you he got bored (or "je something something"). Sometimes he just seems like a very 'busy' kid, like he always has to have something going on. And I'm glad that he finds life so hilarious but I could really do with him listening a bit more seriously sometimes. Any advice or comments or even telling me "oh no, he's completely 'normal'"? via /r/Parenting http://ift.tt/2guy1ud