The song is Ievan polkka by Loituma. The flash is apparently called Loituma girl.
Loituma is a Finnish band that sings traditional Finnish songs with such a strong dialect that I can barely understand the lyrics. The part in the flash total gibberish though, and parts of it sound more like Swedish than Finnish.
Here's a live performance.
Edit: Oh, apparently it's in my native dialect. Well I suppose that explains why I understand anything of it. =P







