Hanezeve Caradhina is a song in the OST of Made in Abyss, composed by Kevin Penkin and sung by 斎藤洸 (Takeshi Saito).
Its composer, Kevin Penkin, tweeted this when asked what the lyrics meant:
It's not a real language, as we thought it would be better with this track to keep a certain amount of ambiguity in the vocals.
— @kevinpenkin, 2017-10-09
I decided to construct a language for it and imagine some meanings out of it in 2017 nevertheless.