I think that a multilingual US would be great. I'd love to learn (and then be able to use) Spanish, but I like languages and pick them up fairly easily. I imagine that for people who struggle to pick up a language (or have never tried to), the idea that you would be regularly confronted with unintelligible information is scary. Where I live, in Vermont, the impact of the growing presence of Spanish is fairly minimal -- we are almost the whitest state in the nation (not that I'm proud of it). One recent controversy in Burlington (the state's largest city) is the growing number of school children for whom English is not their first language, due to a recently-started Refugee Resettlement program.