The U.S. has many people from different countries with different cultures and they can celebrate their culture here in the U.S. The high school that I'm going right now is a public school and we don't wear uniforms but, we have a dress code.
Here are some of the rules (the last one, I'm not sure about the thickness but, it's about 2) :
1. make sure pants are about fingertip/fingernail length down
2. don't wear anything gang related
3. if you wear clothes that may show bra straps, make sure they're about 2 millimeters thick (or 2 cm)
My high school also teaches foreign languages: American sign language, French, Spanish, German, and Japanese.
That's all I can tell you for now. Hope this information helps. :)