Although English isn't the national language of the USA, it is the de facto language of our country and has been so since our settlement by English speaking peoples in the early 17th century. Although the French and Spanish once owned and occupied large portions of our country, the most densely populated parts of America have historically been English speaking and subsequent events over history have made English the dominant language throughout this country. The controversy over what language should be spoken in America has been with us since our inception. In fact, in 1753, Benjamin Franklin stated in reference to German immigration:
"Few of their children in the Country learn English; they import many Books from Germany…. Advertisements intended to be general are now printed in Dutch and English; the Signs in our Streets have inscriptions in both languages…. they will soon so out number us, that all the advantages we have will not in My Opinion be able to preserve our language, and even our Government will become precarious."
Benjamin Franklin's point was well taken and is applicable today. While I don't have any issues with private enterprise putting up signage and conducting business in non-English languages, I don't believe that it is wise for government agencies, be it federal, state, or local, to conduct business in any other language than English.
One should look upon language as a form of taxation. If you wish to be a part of this country, it would behoove you to learn to speak and write English. If one makes this a firm foundation of what it means to be an American, than peoples that are non-English speaking will either assimilate to our nation or remain somewhat separate and apart. That is an individual choice. The more that our government encourages or inadvertently helps residents to maintain their own language in lieu of speaking English, the greater overall disservice we provide them.
It's tough learning a new language, especially if you are an adult, but technology has never been better and the logistics to help people learn in this country are quite strong. Providing people the option of listening to directions in languages other than English, taking tests in languages other than English, and so forth, only encourages them to remain set in their ways while residing in America which is an English-speaking nation.
There is nothing wrong with knowing two languages or more, in fact, I encourage it, but those that fail to learn English have too often the means of using crutches that we provide to them and will not let them go, which fails both ourselves and them.
Not only is English important because it is the language of the USA, it is also the de facto business language of the world, making it even more valuable as the language of choice. While it may be your prerogative to learn or not to learn English, not learning English puts yourself in a vulnerable and undesirable position. Speaking English is an invaluable way to communicate your ideas, desires, and viewpoints and readily gives you the opportunity to receive the same.
This is a country united, and in order to remain so, we should, at a minimum, be speaking the same language.