The End Result of multiculturalism

So, yesterday, I took the day off and went sauntering about New York City with some friends. At one point, I found myself eating lunch at a local Wendy's restaurant. As I was waiting in line, a couple ahead of me, clearly not from the area (had a heavy Slavic accent)is trying to order a burger, fries and drink a la carte. The Nuyorican cashier, not exactly fluent in the English language herself, is trying to explain to this poor couple about combo meals.

And clearly, Miss Nuyorican is from the "Scream-louder-if-they-don't-undertstand-you" school of communications. All the while, she's chattering along is Spanish to her cohorts and saying some fairly derogatory things about the hapless couple (the TrekMedic is fluent in Spanish, Portuguese and Italian, BTW).

Finally, I stepped in and tried to explain everything to the couple myself. They understood me without a problem.

Then my turn came up,....more muttered Hispanic nonsequitors. Imagine her surprise when I proclaimed, loudly, "Si va a vivir en este pai­s, aprenda la lengua, pendeja!"

Not surprisingly, they got my combo order wrong.....

But the point to all of this is simply, "Why isn't English enforced as the language of commerce in its own country?" I can understand the out-of-towner couple, but someone who has lived here for years (she had a definite Bronx accent to her Spanish)?? Since when did our "melting pot" become a "salad bowl??"