They can learn English relatively quickly as I learned Spanish relatively quickly.
I was working in Rio Grande City (on the TX border) a couple weeks ago. Stopped by WallyWorld on the way to the hotel. I was the only gringo in there. Checkout girl spoke English very well, no accent at all, except for her South Texas twang. My local WalMart is a different story (NE TX), the black and white youths can barely speak English.
I hear Spanish all the time here in lines. There seems no great effort to learn English.
American English speaking workers are out on the street for not speaking Spanish these days.