I can say the only part that vaguely resembles any form of latin is "flavum" but that doesnt sound like what shes saying anyway. Sounds more like "flay-vun" if the word flav-un was however flavum the stresses wouldnt make it pronounced anything like that anyway. But she said in an interview the words mean nothing and its just following the soul of the music. I think were avoiding what the point of the song is entirely. The song expresses feeling you could not express in words in any language. If an angels sang to you, you couldnt understand it but you know they are singing about something that you could not express in words. Something more beautiful than anyone could comprehend.

regards.