Hmm... immigrants are Americans. I assume you're referring to a cultural attitude toward language or the second and third generation of immigrants or a specific subset of ignorant and racist Americans? My Italian family immigrated to the US in the 1900s and they claim they didn't teach us Italian because they were proud Americans (eye roll), but it may have been they felt discriminated against and wanted to protect us.

Most native English speakers don't learn foreign languages - Australia is the worst in this category. The US doesn't have an official language, and some Americans are rude to immigrants who don't speak English and/or they expect to communicate in English in other countries, but a lot of languages are spoken in the US.

It is a shame many Americans aren't bilingual, and I believe we should learn Spanish along with English from Kindergarten. It is only because of my interest to learn Spanish and live abroad I've had the remarkable experience of learning a foreign language.

Also, many Americans are too poor to travel overseas, and studying a foreign language in school is one hour a day, five days a week, and two to four semesters. Languages need a lot more effort than that. It's pathetic.