Yes it is, I was in San Diego, CA and couldn't even place a special order at McDonalds because I didn't know the language.
Certain areas of the country (and specially in California) knowing English only is not the greatest idea. Suffice to say that even in an environment where there are "official" translators at work, the translations are rife with errors.
Bueno hombre si quieres tranquilidad, debeis aprender Español si solamente para defensa propia.