Of course it is a low confidence answer for that non-English but literate population. I’m not saying that 100% of those called illiterate are actually literate in another language. I’m saying that the statement that the illiteracy rate is as high as posted is likely wrong because it only accounts for English.
The “may” statement you’re taking issue with is a quick attempt to find out possibly how big that non-English but literate population might be. Its not a definitive answer. You’re welcome to spend your time chasing a more precise number. I’d exhausted my interested when I got my number.
I’m having trouble seeing the mental gymnastics to get that reading when I’m saying that the immigrants are unfairly being called illiterate, when they ARE literate, just in a different language.
I’m discarding any of the statistics from that page I linked because I don’t trust their methodology. I linked it not to support OPs argument about the rate if illiteracy, but to discredit it for being questionable based. The stats from my linked page match much of the stats from their linked page. My guess is that both draw from the same flawed measures and should not be trusted.