Sixty percent of the population of Belgium speaks Dutch, lives in the northern region called Flanders, and are called "Flemish." The other forty percent speak French, live in the southern region called Wallonia, and are called "Walloons." There is a peaceful (so far) independence movement in the affluent Flemish region of Belgium. We hear very little about it here in the U.S.
This article from the International Herald Tribune is a decent introduction to the issue. Countries with two official languages, like Belgium and Canada, are inherently unstable. Understanding this fact makes it important to require that everything we do here in the U.S. be done in English.