"Also the employment rate ain't going down just because they force an American family's 3 years old child in kindergarten."
I suspect what they are trying to avoid is kids arriving for entry at school with little or no native language ability. The kids don't have to go to kindergarten to learn it, but they do have to have a language assessment to make sure they're ready; and the letter included mention of language tuition if they're not.
I think it's heading off the problem we have in the UK, where it's not unusual for a class of 30 kids to have a dozen languages between them and half the class not speak enough English. And that means that the entire class is slowed down while things are either done multi-lingally or kids pick up enough English to get by.
And they'll just have sent it to everyone in the category that matched. Chill. My government sent me a tax bill for two thousand pounds last week and when I phoned up they said "Oops. Yeah.. don't pay that. That was a mistake..."
Systems screw up sometimes.
"That language test a lot of my Dane friends cannot pass."
Yeah, well, I keep failing the British citizenship test :-)
It's full of stupid things like needing to know how many muslims live in the UK and the dates of bizarre acts of parliament.
Whereas I'm British because I know not to talk or make eye-contact on the tube...