The most famous of all Finnish composers is surely Sibelius. His Latin name is that of his originally Swedish-speaking family, though he was born in Finland when it was a Grand Duchy within Russia, and his parents educated him in a Finnish-language school. In Latin (and in Swedish) the name Sibelius would have stress on the second syllable: Si.bé.li.us. But in Finnish there is an invariant rule that all words are stressed on the first syllable. So how on earth do the Finns say the name of this celebrated composer and Finnish nationalist?
The answer is simple enough, and raises an interesting point. If you are a completely uneducated monolingual Finnish speaker, you would say Sí.pe.li.us. (I wrote p, not b, because Finnish doesn't really have b at all in names.) But if you are an educated person and a European sophisticate, you will break the Finnish rule and say Si.bé.li.us, just like a Swede or a Roman.
Here we see a complete pulling apart of the usual prescriptivist assumptions. It is standardly alleged to be ignorant and lazy people who break the rules and corrupt the language with foreign borrowings and speak it badly. Educated people, it is assumed, know the rules and speak correctly. However, in this domain it is the ignorant people who say it "right", if we take the usual Finnish stress rule to define what is right for Finnish (and I don't see what else we can assume). Educated cosmopolitans say the name of this great Finn in a clearly un-Finnish way — and pick up kudos for mangling it in that way.
It's the same with other aspects of the phonology. For example, Finnish doesn't allow a two-consonant cluster at the beginning of a word, so (as Sally Thomason recently pointed out to me) the word for "stalagmite" is talakmiti, pronounced tá.lak.mi.ti; but if you are a Euro-sophisticated geology Ph.D. you will say stá.lag.mi.ti.
This shouldn't be too surprising: English speakers who don't know any French say "vinn blonk" and "restront" and "jeaner" and "notra dayme" while Euro-sophisticated English speakers attempt pronunciations a lot closer to the French vin blanc, restaurant, genre, and Notre Dame. The sophisticates deliberately anglicize less. And gain prestige by corrupting English with Frenchisms.
When it comes to pronunciation, it's clearly the ordinary untutored folk who learn the rules more deeply and follow them more accurately. Yet in grammar, for no apparent reason, it is typically assumed that the ordinary folk have no idea how to deploy their language correctly. Doesn't seem quite right, does it?