I've never spend time on Finnish forums, so, I can't really compare the English forum language and Finnish forum language. The only problem I have with English is that I know there are lots of subtleties I don't recognize. I am pretty good, but I guess I'll never be good enough. If I want to say something, I usually am able to say it, it just might lack the tone I was going for.
I've thought about this question a lot when I was exchange student. The words are especially interesting. In Spanish they have different "grades" of love (te quiero, te amo), for example, which is unlike Finnish or English. And I see this as a reflection of their more easygoing relationship culture.