I think it's due to English being the language of commerce and for the last 300 years English speaking peoples

Have been the number one global and economic power

As for Spanish speaking Americans with in a generation or two they speak just English and take on the American culture

That's happened throughout America's history with the integration of swarms of German speakers

In England I was speaking to a British Pakistani person born in England he can understand his native language

But can not speak it

It's a true talent to learn new languages and become part of the culture by reading their literature

Many of my professors could not speak or read of a languages but the ones who could had a greater depth of knowledge

Because they could read what people in foreign countries are writing about such as

Reading newspapers from Maji Japan after 1868