I believe “blooming” would be more accurate

This are simply called digraphs, the same as spanish “ll”

Yeah, Polish also used to call March “brzezień”, which means the time in which birches grow

With Polish for example, we have 2 month that are currently named after Roman calendar, even thought all 12 of our months used to have their own names

Seconding Audile, it’s great

I recommend Airplane mode or getting this https://www.f-droid.org/packages/com.kaajjo.libresudoku