Kajiura said herself more than once that lyrics like these have no meaning. Apparently, they're just there to use vocals as an instrument more efficiently (you can't do with the constant "aaaaaaaaaah/ooooooh/lalala" all the time, I guess). Then again, Kajiuran does have some semblance to Romanic languages.
It's known that Kajiura is an opera fan, and I heard that in Italian operas, the Italians themselves admittedly understand about every tenth word or so.
Stretching a line over elaborate vocal works does that. And they enjoy the music anyway, with the lyrics more as a special kind of arrangement. I wonder if Kajiura created her "language" with this in mind.
