WOW. EXCELLENT post! And the influence on illiteracy is great info. Thank you.
It is totally true. Look at the literacy rates of countries south of the border, excluding Chile, and you will find 70%+ illiteracy.
We deal with it all the time in California. Our literacy programs are directed at helping them achieve some level of literacy in their original language and then we help them achieve a level of literacy in English so they can function at a higher level in American Society.
Now, go to any report you can find, regarding LDS growth rates and you will find that total numbers are coming from places that have challenges emphasizing competency in their respective languages, with the highest percentage illiteracy outside major cities, which is where you will find LDS success in converts.