¡Ask a Mexican!
Possible questions -- maybe you have better ones:
-- how come mexican kids don't look you in the eye or talk during class?
-- what's the deal with parents allowing girls to get their ears pierced so young and wear such tight clothing in elementary school?
-- how can you tell if a kid is mexican or puerto rican or guatemalan without asking him or her directly?
-- how come the mexican kids don't get along with the puerto rican kids, and vice versa?
-- how come mexican parents don't come to parents night or ask questions about how their kid is doing in school?
-- the mexican boys seem to pick on each other a lot -- what's with that?
-- what are five words in spanish i need to know if i'm teaching in a school with lots of mexican kids?