What is the meaning of the Japanese-like chanting in some Fire Emblem: Three Houses tracks?

There is a persistent Japanese-like chanting that occurs on some songs, most notably the following tracks:

• Main Theme (English & JP versions)
• The Spirit Dais
• Apex of the World (English & JP versions).

There seems to be no official lyrics. A fan interpretation of the song is as follows:

Negai natsuragi, mushi kire mamoru
mugirashugenahira gure ni ga no gen ni
tirabo nanogabo, moru goshi natori
shiramo gabo shuti re no rezo bori cazo

When those lyrics are placed into Google Translate, it is only partially translated. The first line is translated into “I want to relax and protect you”, but everything after fails to get translated.

My questions:

• What language is being spoken in the background? At times it sounds Japanese, but there are syllables pronounced as if they were Latin, and not Japanese (for example, “re” being pronounced as “ree” in the chant as opposed to “ray” if in Japanese)
• Does this full chant have any sort of meaning? Or is it just random gibberish to add to the “mystical” effect of these songs?