We had 2 groups enter our school last year--one was a family of hispanics, one was a family of Thai (I THINK they were Thai). All were given ESOL classes. By the end of the year can you guess which group were speaking English (not perfect by any means!) and able to converse simply. Yep, the Asian group.
Their family structure was unlike any I've seen. The parents and grandparents and aunts and uncles sat with their kids every night from 6:30 until 10:00 and everyone worked on HW or read or wrote in a diary. No exceptions--and no TV either.
Asian, Indian, Eastern European (primarily Russian). NYC has a system of what is euphemistically called "Specialized High Schools." These are schools in which testing is mandatory for entrance and they only take the top 2 or 3 percent. Basically X-Treme Cherry Picking out of a study population of over a million. These kids are filling the specialized high schools.