The people of Louisiana should be ashamed...but they've been trying to eradicate the French Language from their state for decades now, anyway.
''Everyone is free to speak whatever language they'd like.''
It would be perfect if every American thought so, but the fact of the matter is that not everyone in the United States does have this viewpoint. You hear many people complain about some long-time immigrants or newcomers that do not speak a word of English, and how it upsets them, is unacceptable, etc. That is when having English as THE official language of the United States would ''help'' matters. Right now, since there is no official language constitutionally, no American has the right to complain about such-and-such person not speaking English nor do they have the right to FORCE anyone to speak it. So I'm sorry, but if English doesn't need ''an official stamp of approval'', then stop complaining about people not speaking it in your country.
So why? To me the argument of ''we have a myriad of languages spoken here'' is irrelevant when Americans keep saying ''the majority of people speak English'', one nullifies the other. There is a myriad of languages spoken in Canada as well, surely not as many, but proportionally you could compare, and yet we've narrowed down our official languages to the two most spoken ones.
If the U.S. ever had to make a choice, I would go for English AND Spanish, join the bilingual family!
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edit: Andrew: No, not every cultural aspect needs to be written down and made official, but language embodying the corner stone of one's culture and to a larger extent, of one's civilization, it seems crucial to me that a language be protected, if not the whole culture or society identifying itself to it may fall as a consequence.
Americans have never really grasped the importance of language in their society, being speakers of the world's lingua frinca (along with the Brits), which partly explains their low interest in learning foreign languages. Language, however, is everything.