This paper was addressed to an American audience in response to Mary Louise Pratt's Una Lecture, “English-only vs. National Security: Language and contemporary geopolitics”, at the University of California, Berkeley on March 16, 2004. It makes the point that it is not enough for Americans to learn foreign languages; they must also understand that speaking a language other than English is an opportunity to see things from a different perspective. Increasing the glossodiversity of the U.S. should be accompanied by an increase in semiodiversity, that is, an opening up of language learners to the diversity of worldviews both in the U.S. and in the world today. The paper is followed by responses by Alastair Pennycook and Azirah Hashim, to which Claire Kramsch gives a brief reply.