In my experience as a language learner, there have been two types of languages. One type is taught as having the same kind of grammar its native speakers think it does. I think German was one of these. We learned cases and articles and what not in German, but we called them by names native speakers would know, and if it came down to it, a native speaker and I could have conversed about German grammar and been on more or less the same page.
But there's another kind of foreign language - the kind of that requires a secondary, additional grammar to be superimposed upon it for the benefit of of its (second-language) learners. Japanese was like this - we had two verb types, five "bases," and two forms...and a native speaker would have had no idea what I was talking about if I described this system. It's a grammar that was created for the use of outsiders like me.
I've realized that Finnish is like that, too. We learn verb types and word formation rules and other quirks that native speakers never have to. I suspect a true scholar of the Finnish language who is also a native speaker might be aware of these features, but otherwise, it's left to the Finnish for Foreigners teachers and their students. I can't count the number of times I've asked a Finnish friend about this or that feature of the language (k-p-t change, i-ending adjective rules, six verb types, ainesanat, etc.) and had their response basically be: "..." It's interesting to see what awesome linguists have come up with to make certain foreign languages like Japanese and Finnish more accessible to learners.
Two footnotes:
1. Today in class, my Finnish teacher was telling us how to say prices in the local dialect, and then she added, "oh, but you only have to say 'euroa [euros]' after even numbers." There was a silence as we students took that in and then I literally laughed out loud. I couldn't resist. I told her that was the craziest language rule I had ever heard. After prices ending in 0, 2, 4, 6, or 8, you had to add the "euros," but after 1, 3, 5, 7, 9, you didn't?!?!? What fresh hell was this? But no, it turns out she meant rounded-off numbers. So, just like in English, you could say "that's one-fifty [$1.50]" but would have to say "that's five dollars [$5.00]." I breathed a sigh of relief when she explained what she meant, but the scariest part is that my Finnish teacher told me a crazy, crazy grammar rule that was contrived and awkward and unnecessarily detailed...and I believed it. I believed that was something Finnish would do to me.
2. Yesterday Sterling was flipping through one of his many treasured car/truck/plane books from the library. He knows all the vehicle names in English and many in Finnish, too. He came across the page with a motor home and couldn't quite bring up the Finnish word. So he guessed, and said, "motor home-y?" It was actually a good guess - the joke here is that to make an English word Finnish, you just add -y (or -i) to it. Good job, Sterling. He gets it.