@riley @dancingtreefrog I did think it sounded a bit late! But my picture of the dates of some of these things is pretty vague :-)
Lots of interesting stuff in all that!
Re the umlauts, at some point I looked at some of the various Wikipedias' articles¹ about the letter å, and was surprised to discover how early it was used in Swedish compared to Danish and Norwegian. I don't remember the actual dates now . . .
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¹ different language Wikipedias