7bit Maybe one reason the El Paso school districts are pretty successful at teaching English is that transition is automatic and everyone knows it.
Fourth grade is the transition year and fifth grade is the mainstream year.
I was concerned about my nephews when they entered school because only Spanish was spoken in the home and their mother spoke no English. They did beautifully. One thing that does happen is that children begin using English as they play, so even after school they are using some English. And even in a neighborhood where Spanish is the dominant language, many parents will speak English and some of the children will speak English fairly well. Then there is the younger child phenomenon.