A new term?
No 🙂 as not much of Adûnaic is known, for the film David Salo (the linguist who did most of the translation-stuff there - Sindarin, Quenya, Old English, Black Speech, Khuzdûl, all those things) invented a language based on Adûnaic, using all the known Adûnaic grammar and vocabulary and also the phonetic system, but inventing new words and grammar details where it was necessary. It was for example used for the lyrics of the Nazgûl-chants in FoTR 🙂 the text I had in my very first sig 😊
Morthond
"blackroot", a river in Gondor