The LORD shall bring a nation against thee from far, from the end of the earth, as swift as the eagle flieth; a nation whose tongue thou shalt not understand; A nation - from far - Probably the Romans.
As the eagle flieth - The very animal on all the Roman standards. The Roman eagle is proverbial.
Whose tongue thou shalt not understand - The Latin language, than which none was more foreign to the structure and idiom of the Hebrew.