I don't believe any one group of people actively uses TWO languages at the same time, in any country. In Canada, they have French and English as official languages, but that's 'cause there's a large French native population that's existed there for a long time. People still speak only one language in Canada, you either speak mostly English, or mostly French, and then they learn a little of the other. Nobody starts speaking both languages perfectly well by themselves. Being bilingual is very difficult because the only way you can be truly bilingual is if a set of parents has a child and the parents know one language, and the child lives in a country where they speak another language.
In the United States we see this occur in the Hispanic community. That's really the only way you can create a truly bilingual person. The parents who have come into this country are not bilinguals, and even if they learn English, they will speak a very elementary English. So the parents are Spanish-speaking and having learned English as a second language. They're NOT bilinguals. That means that true bilinguals form a small portion of the population. The reason why they distribute pamphlets in Spanish, is because older hispanic immigrants speak mostly Spanish, and an older person is gonna have a hard time learning another language. English is a language that takes years to master. If you want to speak English at a collegiate level, it usually takes people till they're about 23-25 years-old to master it and that's after a lifetime of studying throughout their youth.
The thing you have to understand about immigration is that the parents are probably never going to learn English beyond the elementary, but the children will become fluent in English, and they may speak Spanish. The grandchildren of immigrants, however, are almost always going to be able to speak English, and little or almost no Spanish. The great grandchildren will be the generation to speak English exclusively, if any of the previous generations have not taken it up already. This is a normal habit of immigrants. Throughout the history of the United States people once spoke Italian and German, but eventually people assimilate. This is what will happen with the Hispanic community as well.
Anyway, it sounds like you're getting a little paranoid, when really the outcome is already set in stone. I don't believe that scenario in the Utah State Legislature will ever play out, so stop worrying about it!