How does this report give us insight into the changing nature of bilingualism in the United States—not only the languages and groups involved, but also the places where languages other than English...

How does this report give us insight into the changing nature of bilingualism in the United States—not only the languages and groups involved, but also the places where languages other than English are likely found and reasons why? Why, according to the report, are data such as those presented here useful and even necessary?