Ad. optative grammar.
The Adûnaic optative mood was represented by an auxiliary (SD/439). The optative mood is used to for the expression of a wish: “May you be happy in your new home”. Quenya has a similar construct: Q. nai “maybe, may it be that”. This Quenya element actually appears in the draft Adûnaic sentence azrē nai phurrusim akhās-ada “seas might-flow Chasm-into”, changed in the final draft to azrîya du-phursâ akhâsada “that the seas should gush into the chasm”.
For this reason, I think both of these sentences may be examples of the optative mood, but most other authors have suggested it may be the subjunctive instead. Many languages use the subjunctive for the expression of a wish as well as hypotheticals, so it is hard to say how Adûnaic may have used these verbal moods.
There is another sentence that may be an example of a “negative optative”: bâ kitabdahê “Don’t [you] touch me!”, with the negative element bâ “do not”. This sentence was translated as an English imperative command, but Tolkien did not list the imperative as one of the verbal moods of Adûnaic. Carl Hostetter and Patrick Wynne suggested (VSH/25) that the sentence might be an optative, so that its literal meaning might be “May it be you not touch me”. This sounds plausible to me; it is possible the Adûnaic generally expresses commands with the optative mood.
Reference ✧ SD/439