Ad. participle grammar.
There are a few Adûnaic adjectives that appear to be (passive) participles, that is adjectives that are formed from verbs:
The participle suffix seems to be -ân¹, as suggested by most authors (VSH/30, LGtAG, AL/Adûnaic, NBA/31). There is something peculiar about these adjectives, however. First, unlike normal adjectives (SD/425), they appear after rather than before the noun they modify: Zigûrun zabathân “Sauron humbled”, Anadûnê zîrân “Númenor beloved”. Second, there is a similar suffix -ân² used to create agental nouns from verbs:
It is unlikely that the same suffix would be used for two very different grammatical functions, noun formation and adjective formation, both from verbs. Perhaps all of these cases are actually nouns, zabathân “*humbler”, zîrân “*lover”. The apparent use of these nouns as adjectives could be a specialized adjectival genitive construction:
In such cases, this construct might function as a kind of subclause in the passive voice: “Sauron who is humbled”, “Númenor who is loved”. This would resolve the ambiguity between -ân¹ used as a participle suffix and -ân² for agental-formation, but introduces a new problem however: how would Adûnaic distinguish between sentences like “Sauron who is humbled came ...” and “the humbler of Sauron came ...”?
Perhaps the location of the subjective inflection is used to make this distinction. In the first example below, Sauron is the subject, and in the second, the humbler is the subject:
In the case of Anadûnê zîrân, which does not use the subjective inflection, it may be the verb’s pronominal-prefix which indicates the subject:
Alternately, this sentence may simply have two nouns in apposition, as indicated by the gloss of the final manuscript version:
This is all quite speculative, but if true, the suffix -ân might always be used to form an agental noun, which can in some instances be used as if it were a participle adjective: when it follows another noun marked as the subject of the sentence.