What's the accepted explanation behind the vast racial divide in scores? Is it a proxy for poverty? Is it a cultural issue? My understanding is that white + asian Americans, on PISA tests at least, perform at a level that would put them in the top 5 countries in the world, were they alone. I'm not interested in race-based theories -- those seem obviously wrong to me -- but that fact does seem to stick out. Can you explain what the prevailing theory is? Or should I be ignoring that data?
Also, do you have data to support your "rare American who speaks or reads any language besides English" gibe, or was it just offhand snark? The famous Arne Duncan bit cited people who speak more than one language in their home, and the only other data I could find was a gallup poll (suspect already) about people "able to have a conversation in a second language" -- about 25% of Americans.
EDIT: I should stress that my natural bias is irritation at arguments that try to layer European policies over American populations. Forget race -- I don't think it's interesting -- but it seems a lot easier to to design an education system for a culturally homogenous society than a culturally diverse one. This is akin to when people were exclusively blaming the American health care system for a higher mortality rate rather than, say, the massive obesity rate in this country.