Are u serious? America is not a nation. Nations have their own languages.
That is wrong imo, a language can play a big role in "building a nation", but it's not fundamental to create a nation's idenity.
In Austria,Germany and Switzerland(well, most of the Swiss) people speak the same language: German (Deutsch whatever), but still, they are different nations... the same could be said about Ireland,Wales,Scotland : i really doubt that a big part of the population of those countries can write and speak fluently in Gaelic; the main language over there it's Englis, but that doesn't mean they are English .