"Nearly four in 10 El Paso County residents who were surveyed said Spanish was their dominant language, while a similar proportion said they communicated in two or more languages. One in five said English was his or her dominant language."Read what you posted...4 in 10 said that Spanish was their dominant language.
My parent's would answer the very same way, it doesn't mean that they don't speak English, they speak it quite well, but Spanish is their dominant language nevertheless.
Then another 4 in ten or so admitted to communicating in two or more languages. Again, it doesn't mean that they don't speak English.
Only 1 in 5 said that English was their dominant language.
By "dominant language" they probably mean the language that they dream, and think in. That takes a long time to happen.
I don't see where you proved your point here.
There have been several articles in the papers here --one third of the people don't speak English or speak no more than a handful of words in English and many have lived here over 20 years. One fifth speak only English or no more than a handful of words in Spanish ---in between there are varying levels of English proficiency but even they are not all fluent. Economically the area is in trouble and some are beginning to think part of it is language. It's a little hard to assimilate when you won't learn the language of the majority.