Its from the first half of the ritual orgy segment in Eyes Wide Shut. I knew it was something sung backward (you can tell by the way the sound sort of fades in and is stressed at the end, opposite of normal), so I recorded and reversed it. There are two vocals, the lower-toned one is chanting in a language I'm not certain what is, but he ends with "Allah, Allah, Allah". The higher-toned voice is chanting in Romanian. It's difficult to make out, but it ends with "si binefacator"-something-something-"acestui om". I'm pretty sure it's a quote from a religious text but I'd like to know exactly what.
It's repeated a few times, I'll upload the clearest one in the morning (it's late now).