Hamish Reid writes:

None of that really answers the question: in what sense is Spanish a
foreign language in the US? As several people have pointed out, it
predates English in these parts by a long way, and has been spoken
continuously 'round here by immigrants and native-born citizens alike
for all of that time.

It is not the predominant language in the U.S., irrespective of any historical
or minority use.

Would you call Lakota a foreign language in the US?

Yes.

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