Sunrise ~LOVE is ALL~ lyrics

[music_*]

A question about the lyrics!
Okay, here's the thing. I'm currently studying Japanese and there's this part in the lyrics I don't get.
The unofficial lyrics go:
大きな愛
大きな声
something like that.

So my question is: isn't 大きい an　い-adj?
Why is it paired with な？
It could be just to fit the song, but I wonder if it's something that the Japanese do in real-life; or is it just for Ayu's lyrics?
Something like that~
Could be my mistake since the lyrics aren't official.
And this might even be in the wrong place.

[keikeiaznqueen]

Sometimes ookii is written/said as ookina. I think the original form is ookii, which makes it an "i" adjective. But then it is also interchangeable as a "na" adjective. I asked the same question to my Japanese teacher before. It's just an exception I think. Ookina is not grammatically incorrect.

The same can be done with chiisai and chiisana.

[Heavenly]

do we have the complete lyrics somewhere ??

[noidea]

^ The song leaked a few hours ago, wait a little xD

[music_*]

@keikeiaznqueen: YAY! Thanks for this

[Mitkki]

大きな

大きい