I grew up in Southern California, and as a kid, we had a family of Mexicans living next door. Mr. Hernandez worked hard, and they had the neatest house and yard on the block. They also spoke English in the house. When Grandma Hernandez refused to learn English, she got sent back to Juarez, because Mr. Hernandez felt that if they were going to be Americans, they needed to speak the language of the land.
Pity there aren't more like him. There are fifth and sixth generation American citizens who don't speak a word of English now.
I spent a couple of years in beautiful (not!) McAllen, Texas. If you needed help in the local Wal-Mart, you had to look hard to find someone who spoke even 'Spanglish', let alone English.
I happened to be there for 9-11, and got a huge kick out of listening to the screaming and yelling as the local National Guard Marines parked their 8
wheel mini-tanks at the border crossings and CLOSED the border. Period. It's a damned pity they didn't leave it closed that tight.