Finnish wasn't even a written language until the 1500s because Swedish was the official language.
It's always been interesting to me that nations that were once possessions of Catholic countries have fared worse to this day than those whose exploiters were Protestant. Sociologists have long attributed this to the Protestant Work Ethic, but that didn't seem enough of an answer and yes, Catholicism is very hierarchical and authoritarian and sure, there's the whole issue of birth control but something else I hadn't considered till this trip was right before my nose.
When the Nordic people went Protestant, they did so completely and rulers required compliance. One of the main tenets was that people should not rely on priests to tell them God's word, but should study it themselves. Not just should study, but MUST. But reading the Bible required literacy, which was when Finns began to learn to read, as it was for them a requirement of confirmation to read scripture. The first Finnish language publication was the New Testament.
Literacy. That's what made the difference. Luther and Gutenberg changed the fate of the world.
And as a note about the Finnish version of Lutheranism - the historical museum has a nice collection of statues and such from the Catholic era because, unlike many others who converted, the Finns didn't want to destroy the icons. They had all been donated to the churches and to destroy them would be disgracing their donors which no one wanted to do.
And now, Finland is ranked as the most literate nation in the world.