I had the same problem coming from the same Germanic/Romanic languages as you, trying to learn Finnish. It's not just the vocabulary, the whole construction and modality is often different, and it's hard to map things one on one. Then I learned Swedish, and it was just a funny dialect between Dutch and German.
Yes Finnish is way out there. We're raising our kid bilingual EN/FI, and I am really curious to know how he will align these two languages in his head, and what kinds of insights he will get. I suspect he will be a sponge for additional languages.
