Why should immigrants learn English in the US?

Maybe these examples of immigrants to the U. S. will shed some light on why it would be a good idea for an immigrant to America to learn English:

Charles Atlas, Italy, Bodybuilding
Mikhail Baryshnikov, Soviet Union, Dance
Irving Berlin, Russia, Music
Frank Capra, Italy, Film
Claudette Colbert, France, Film/Theater
Xavier Cugat, Spain/Cuba, Music
Karl Dane, Denmark, Film
Albert Einstein, Germany, Science
Gloria Estefan, Cuba, Music
Felix Frankfurter, Austria, Law
Andy Garcia, Cuba, Acting
Marcus Garvey, Jamaica, Politics
Kahlil Gibran, Lebanon, Literature
Arshile Gorky, Armenia, Art
Sol Hurok, Ukraine, Theater
Al Jolson, Lithuania, Show Business
Elia Kazan, Turkey, Film/Theater
Henry A. Kissinger, Germany, Advisor
John Kluge, Germany, Business
Alfred Levitt, Belarus, Art
Bela Lugosi, Hungary, Film/Theater
Zubin Mehta, India, Music
Hakeem Olajuwon, Nigeria, Sports
Hyman G. Rickover, Russia, Science
Edward G. Robinson, Romania, Film
Knute Rockne, Norway, Sports
Arthur Rubinstein, Poland, Music
Carlos Santana, Mexico, Music
Arnold Schwarzeneger, Austria, Bodybuilding/Acting
Igor Sikorsky, Russia, Aeronautics/Helicopter
Gene Simmons, Israel, Music
Lee Strasberg, Austria, Theater
Arthur Tracy, Russia, Music/Film
Rudolph Valentino, Italy, Film
Baron von Trapp & Family, Austria, Music
An Wang, China, Technology

Did you figure it out? Each one of the above immigrants had to learn enough English to be successful in the United States.

There's a story in the Bible about this issue with language. It's about a place called Babel, where many people were living. God wanted them to go abroad on the earth, but they weren't. He realized that they all spoke the same language, which gave them a great advantage, as they could communicate unencumbered. As a result, they started to build a great tower. So God said, "Look, they're one people and they have one language; this is only the beginning of what they will do, now whatever they can imagine will be possible for them."

Wow! God's saying, because everyone speaks the same language, they'll be able to do whatever they can imagine. So what happens next? God fiddles with everybody's speech, so that now there are groups of people speaking the same language, but each group's speech is different from the other. So they pack up and head out in different directions. They divided. The differences in speech resulted in division, not unity.

For the U. S. , I'd like to see more unity. Think of what we could accomplish!

Ref.: Genesis 11