I've seen the movie and I've read other works by Niemi. Be careful with the spelling, it's Vittula, where "vittu" means "cunt", and the -la is a suffix for making it a toponym. OTOH, "vitulla" means "on top of a cunt" or "by using a cunt". Also, the original place is called Vittulajänkä, where "jänkä" is a kind of Northern wetland.
The language aspect is interesting, because it takes place in an area of Sweden where they speak Meänkieli, a dialect of Finnish. Swedish authorities consider it a separate language, for the purposes of preserving the special minority status, thus making an interesting case of the language vs. dialect problem.
I don't doubt that Swedish is spoken/understood near the Swedish border on our side, but that probably happens in every border zone around the world. The real Swedish-speaking areas, where many people don't speak Finnish, are found at the coast.