Hispanic Literacy

So, in class I brought up the idea of Hispanic literacy and/or multilingual literacy and there is a little more that I would like to say. First, morning announcements in my school were usually read in both English and Spanish. When Hispanics with non-proficient English skills had to take tests they went to the ESL classroom where there was a teacher to help them in case they had any questions. My school had a fairly high drop-out rate because of the the Hispanic population. One of the reasons the Spanish speaking students tended to drop was cultural reasons. Many of the female students were married when they were 15 or 16 years old, some ended up getting pregnant and found that they couldn't stay in school. Others dropped out because they didn't have a good understanding of what was going on in a mostly English speaking environment (there were only a few teachers that new enough Spanish to communicate effectively with those students whose English was almost non-existent). Either way, these students become part of the statistic of illiterates in the USA.
In groups today, when we were considering a different test format, I thought that one could start by administering an optional test in Spanish to the Spanish speakers in elementary school, and carefully ween the children off Spanish so that by High School they could take the English standardized tests with the other students. However, I now realize that this would only work for those students introduced into the school system at a young age. A large number of the Hispanic students did not come up through American school systems, but immigrated with their families to the USA during their high school years. Now, I don't know a lot (or really anything) about education systems in Latin America, but I'm positive that they do not teach in English. On top of that, the desire to learn English may not be that intense for many students. Their parents don't speak English fluently (they don't need it to communicate in school), they attend churches where services are in Spanish (don't need it to worship), and most of the stores around West Grove (my home town) had Hispanic employees or are run by Hispanics. In essence, within my community back home, the Latin American immigrants have established their own community where they can live well enough without English literacy.
This brings up the same question as Frank's situation. If they have established a situation where proficiency in English Literacy is unnecessary, do they need to work to achieve higher levels?
I would also like to say that a part of the Hispanic population (mainly adults) cannot read or write in Spanish. One would need to teach them reading/writing in their native language before they could become literate in English. So, given the situation above and this here, is it worth trying to teach reading/writing to such Hispanic populations within the USA?

Here is an article from 2005 about spanish literacy:
http://www.chron.com/disp/story.mpl/front/3528735.html

And this is a youtube video that claims that "poor education and poor health go hand and hand": http://www.youtube.com/watch?v=DmkfYB2jACw