My classmates think I'm dumb, I don't think I am though, what should I!

Your poor English? Well...you write better English then alot of people who were born in English speaking countries :)

You just have trouble staying focused, that doesn't mean your'e dumb...it just means you don't focus. You just need to learn to pay attention more, not to please others or so others don't think you are stupid though, just do it for yourself because it will be better for you.
In life, there will ALWAYS be people who think badly of you, just like there will always be people who think good things about you.
Don't let it get to you.
Apparently, studies have shown that watching alot of TV can give you a shorter attention span so it makes it harder for you to focus. Just do more things you need to focus on, like reading or doing projects like making things and stuff like that.
Forget what people think of you in school, your'e only going there to learn so you can have a better future, you wont even know those kids in a couple years when you have a life so why care what they think. Just do your thing and forget em.

There`s nothing wrong with your English. Furthermore, what you describe is just normal for everyone. We all get laughed at when we say or do something funny. The trick is for you to see the humor in it and laugh along with the crowd. They are not meaning to put you down. They just can`t help laughing at something which comes out funny. So enjoy yourself and the humore you create. If you laugh along, everyone will be happy.

Yeah, this happens to me a lot too. But I noticed all the people sometimes fail. Just take it easy, if people see you don't care about your misunderstandings and stupid mistakes, then they won't care either. If they tell you something, just do not start justifying yourself against them, but better tell something back to them. We are all people and all do the same mistakes.

anytime anyone puts anyone down, in any way, its only because they feel they they themselves are nothing (dumb, poor, ugly, etc).

so , be confident in yourself and just let it go, be your own smart confident sensible clever self, whatever they say, and whatever they think

opinion

Your written English is flawless, and it's understandable that you would have trouble hearing words properly in a language that isn't your mother tongue.

My advice: get new friends. Your current friends obviously don't have enough respect for you.

Your English is fine. Ignore the people making fun of you.
Look at your future. You know both English and your native tongue. That makes you more competitive for getting into college than any of the people in your class right now. Use what you have to your advantage.
Yes, college may be a long way off... but keep your eye on the goal.

Your English is great! And no you are not dumb. people are just really mean anymore.. i have the same problem sometimes and i just either laugh with them or just walk away.. Don't let them get to you.. You seem like a really nice person..

Hack their facebook and make them look gay

Hey, you say your grades are good. The thing is, they aren't teasing you because you're stupid... even if you stopped doing anything slightly embarrassing, they'll just look for something entirely irrelevant and use it to call you dumb. A lot of kids these days are just retarded and find amusement picking on people, and they've chosen to single you out.

Really, it's best to just ignore them. If they do anything serious (i.e. pull a prank) you could report it at school. Just focus on getting your grades (which you already are). You'll have the last laugh when you graduate with good grades and the idiots who have nothing better to do in class than find lame things to laugh at will often be the ones working at Burger King.