Koios, British English is certainly intelligible to American children ...it is merely a matter of vernacular.
Similarly,
I had a couple of teachers straight from Ireland when I was little and had no trouble understanding them even through the thick brogue.
I don't mean to be unduly argumentative here, but the sentence in Wiki would prove your point only if it mentioned government documents and if it mentioned that the schools at issue were public schools.
Another thing to keep in mind is something I was trying to hint at - as politely as possible - last night: that Wikipedia really is a questionable source of information ...in fact at my kids' school it is not even considered admissible as substantiating anything.
The reason for that is that Wiki entries can be written by literally anyone.
Thus, the best use of Wiki is to get keywords related to the topic and then look elsewhere.
If it is the case that government documents were translated into German - as an official policy vs. just a favor in some localities - then there should be a record of this on the Internet in places other than Wiki.
Even if you should find such a record, you are talking about nearly 100 years ago and only one language (not most of those groups Lilly mentioned as you wrote previously).
I do not consider that a grounds even for bilingual ed. Please read the goals and designs of La Voz de Aztlan and you will understand my point of view better.
Additionally, how long before the THIRD most spoken language would demand such accommodation also ?
They do not have any power to demand these things except what is wrong-headedly given to them, especially in view of the fact that so many of them are here illegally.