Interviewer: What is 「Kajiurago」?
Kajiura: This so-called "Kajiurago" is actually a constructed language I frequently use, meaningless language fabricated by myself. It's only that I arbitrarily named it "Kajiurago". It's entirely meaningless.
Interviewer: Not even a bit of meaning?
Kajiura: Yeah. Fabricated only for its pronunciation. One thing is that when I wrote insert songs and other songs for anime, I had initially used Italian, Latin, and the like before. Even if it were a non-Japanese song, for scenes whose meaning I cannot match, to use lyrics not matching the work, I don't like that.
Interviewer: Why use "meaningless lyrics"?
Kajiura: Despite the thought that few will understand anyway if English is used, few will understand anyway if Italian is used, I nevertheless have great psychological reactance. When I no longer wished to continue doing thus, I remembered that I could choose constructed language. If you were to ask me about its benefits, it would not be shackled by meaning, allowing listeners free rein for imagination, and I also get a lot more freedom myself.
Interviewer: I see.
Kajiura: The sounds fitting the melody most can be used. There previously had been no choice at times, but to sing unsuitable pronunciations at clearly unsuitable vocal ranges. Totally not a problem when using constructed language. If singing 'a' suits here then sing 'a', if singing 'i' suits there then singing 'i' or 'mi' are both fine. There's total freedom in articulation as the lyrics have no meaning. Therefore there's considerable freedom in singing.