I love this question and have read many fine answers. While "Balloon" comes across too angry, he/she does make good points. However, I think they missed the main point.
If I visit France, I would expect to have to learn a little French. Even if it is only "I'm sorry, I do not speak French" or "Do you speak English"? The same with any other country! Learn enough to get by. If you have not attempted to learn some of the language, people (in general) will avoid you. If you make an attempt at it, they will try to help.
The USA was formed primarily by the English, this was the language which took. In time, English has morphed into a modge-podge of many languages. It will continue to change!
Business owners know that they have to make money to stay in business. To do that, they must cater to the people who live in their community. Thus, they hire people who can speak other languages. Their signs sport 2 or more languages because they know that not everyone speaks English.
There are a number of people in my community who are willing to teach others the language, often at no cost. A great many are willing to learn English this way. And, perhaps, at the same time, have the opportunity to learn something of another language.
Get used to it folks! English will probably continue to be the "Official Language" in the USA, but in order to get along, we are both going to have to give a little. That is until the USA becomes North Mexico. ;-)