As for the Sanskrit in the lyrics of "The Duel of the Fates", it's probably there, but very well hidden. "Mangled" doesn't begin to describe it... I looked into this years ago, and here's some of what I've found. Allegedly, the lyrics are based on a Welsh poem called Cad Goddeu, rendered into English as The Battle of the Trees. One verse of this, in one English translation, goes
"Under the tongue root a fight most dread, and another raging behind in the head"
(I am still baffled as to what this "fight most dread" may be under a "tongue root".)
Anyway, this was supposedly "translated" into Sanskrit, though the translator may not have known Sanskrit beyond being able to look up some words in a dictionary, then broken up and rearranged by the composer into something that sounded good to him. As far as I know, no official lyrics were ever published, but some people have transcribed phonetically what they thought they heard. The result was:
Korah Matah Korah Rahtahmah
Korah Rahtamah Yoodhah Korah
Korah Syahdho Rahtahmah Daanyah
Korah Keelah Daanyah
Nyohah Keelah Korah Rahtahmah
Syadho Keelah Korah Rahtahmah
Korah Daanyah Korah Rahtahmah
Korah Daanyah Korah Rahtahmah
Nyohah Keelah Korah Rahtahmah
Syadho Keelah Korah Rahtahmah
Korah
Korah Matah Korah Rahtahmah
Korah Daanyah Korah Rahtahmah
Nyohah Keelah Korah Rahtahmah
Syadho Keelah Korah Rahtahmah
Then someone, who definitely knew no more Sanskrit than being able to flip the pages of a dictionary (but was a speaker of a modern North Indian language), kept doing so until he found something that sort of vaguely resembled the words above, and announced to the world that these are the meanings of the words in the lyrics. For instance: Matah = head (Hindi माथा?); Rath = speak (??); Amah = give (??) etc.
Others then passed this on as fact, some even adding that it's okay if it doesn't make sense, "because there is no formalised grammar in Sanskrit".
At any rate, I think some segments of the above transcript can indeed be matched to Sanskrit words, e.g.
korah is probably ghoraḥ (unless it's kharaḥ) and korah rahtamah may be ghoratamaḥ, perhaps a rendition of "most dread"
yoodhah is definitely yuddhaḥ
syahdho may be *sya adhaḥ (perhaps matah also contains adhaḥ?)
daanyah and/or nyohah may contain anyaḥ (perhaps preceded by an ablative case ending in daanyah)
There's rather more recognisable Sanskrit in the lyrics of another piece, Qui Gon's Funeral. The (unofficial) transcript says,
Madhurah swehpna, go rahdomah swehpna, morittioo, madhurah, swehpna. There is no translation, but the English subtitle of the song is Death''s long sweet sleep.
I think this can safely be equated to Madhuraḥ svapnaḥ, ghoratamaḥ svapnaḥ, mṛtyuḥ, madhuraḥ svapnaḥ.
Though perhaps we should look for a word meaning something like "long" in "go rahdomah" - but I haven't been able to think of one.
All the best,
Dan