As someone growing up in relatively close contact with Finnish, I can assure you that there's no real common ground between Scandinavian languages (Swedish, Danish, Norwegian) and Finnish. There are loan words, but they are few and far between and in any case does not make for any mutual understanding. I've been so much to Finland that I would really like to learn to at least understand the language, instead of relying of memorized names of foodstuff and the like. Just have to tackle Japanese first.. (and I consider that one an easier operation)
We do have one small language, the Kven language(https://en.wikipedia.org/wiki/Kven_language), which is a sort of "Finnish structure, but with lots of borrowed Norwegian words. But for all intents and purposes, it very much sounds like Finnish.
It basically sounds like the language a Finnish person that has lived their whole life in Norway, and then starts to mix words because they forgot the Finnish words.
But that's about it. I know there are some other dialects, too, but these are all very small-scale languages that are either extinct, or will be extinct in some decades.
Much easier for Finns to learn Swedish, that for Swedes to learn Finnish, IMO. I speak Norwegian and Finnish (lived in Finland when I was young)
Loan words from Scandi are more common than you think. Eg Hei is a common greeting, tykätä is a common verb. For nouns there is even a whole paradigm for loans, a large number of which are Scandi. They are not necessarily easy to recognise since they undergo sound changes eg plaasteri becomes laasteri
Loan words, yes, but that has very little to do with the grammar and structure of the language. "Jag tycker om dig" [sv] translates to "Tykkään sinusta" [fi], which isn't anywhere near the Scandic.
Oh well if I made a spelling mistake that obviously invalidates my whole point. Thank you for teaching me that Finnish is a very special language -- just like the Finns -- such an amazing an unique people ;)
