I have to admit, the idea struck me as un-libertarian, but just about every bit of information I can gather on it shows that some 80% of Americans are in favor of it. It's a popular message, plain and simple. I read an issue paper from the Cato Institute which quoted empirical evidence that over 90% of immigrants to America speak English only by the 3rd generation. My own family is proof of that. My great grandparents spoke only Italian, my grandfather was bilingual and my mother and her siblings wouldn't know Italian from Japanese. This is taken by Cato to mean that no official language is needed. I have read other studies that claim printing government documents in multiple languages is actually working to prevent the immigrant community from learning English, leading to second and third generation children still speaking with an accent or being bilingual.