Yes, in order to make it rhyme the lyrics are... interesting xD Also her voice sounds different singing in English. As I said, it's harder to express your emotions in other languages. Especially if not fluent which I don't know if they are, but I don't think they are.

I want you Nookie!

Hard to find Da

Well, since Russian is their first langauge, it's probably easier to express their emotions in the song in Russian than it is in English.