Adûnaic plurals serve the same purpose as English plurals: to describe multiple instances of the same noun (except for natural pairs, which use the dual instead). The plural is formed with the plural inflection -î- (SD/429). This inflection is added as a suffix to a weak-noun and replaces the last vowel of a strong-noun.

Plural Formation

The plural form of a noun depends largely on whether you are declining a strong-noun (whose last vowel is short) or a weak-noun (whose last vowel is long or a diphthong).

• Strong Plurals: A strong noun replaces its last (short) vowel with the plural inflection î: Nimir “Elf” → Nimîr “Elves” (SD/436, WJ/386); azra “sea” → azrî “seas” (SD/431).
• Weak Plurals: A weak noun adds the plural inflection î as a suffix. If the long vowel is final, the suffix either forms a diphthong or requires the use of a glide-consonant: bâr “lord” → bârî “lords” (SD/251, 438); Avalô “Power, God” → Avalôi “Powers, Gods” (SD/247); nardû “soldier” → nardûwî “soldiers” (SD/438).

These plural formations are fairly consistent. There are only a few variations.

Weak nouns ending in -ê (and -î?): In the standard Adûnaic rules for vowel-combinations, a final long -ê absorbs the plural suffix î, making the plural form identical to the singular: izrê “sweetheart” → izrê “sweethearts” (SD/438). To distinguish these forms, you can insert a linking-consonant n after the final -ê: izrê “sweetheart” → izrênî “sweethearts” (SD/438). It is possible that the same thing can be done for weak nouns ending in -î, but Tolkien gave no such examples.

Weak nouns with archaic strong plurals: Sometimes a weak noun can use a strong plural (SD/435), especially in archaic writing. This can happen for several reasons:

• The noun could have an archaic form that was originally strong: narû “man”, archaic forms †naru → (strong plural) narî “men” (SD/437). Its newer weak plural would be narû → *narûwî.
• The noun could belong to the small class of nouns (Strong Ib, Strong IIb) that used strong declensions despite having a long vowel in its last syllable: banâth “wife” → (strong plural) banîth “wives” (SD/437). See the section on “Archaic Strong Ib and IIb nouns” in the entry on the strong-noun for further discussion. By the time of Classical Adûnaic, these nouns could be inflected with the ordinary weak plural: banâthî “wives” (SD/437).
• Poetic writing sometimes simply uses the weak plural, perhaps to fit a meter: batân “road” → (strong plural) batîn “roads” (SD/247, 435). In normal speech these nouns probably use the ordinary weak plural: batânî “roads” (SD/432).

All of the above examples could also use the ordinary weak plural, so these exceptions can be safely ignored by the time of Classical Adûnaic except for their use in poetry.

Subjective Plurals

In the subjective plural, Adûnaic distinguishes not only between the strong and weak nouns, but also between neuter-nouns (which use the subjective declension -a-) and gendered-nouns (which use the gendered plural subjective suffix -im).

Neuter Subjective Plurals: Neuter plurals in the subjective simply add the subjective inflection -a as a suffix to the plural form. If the plural suffix -î appears at the end of the word, it is separated from the subjective suffix with the usual glide-consonant y.

• zadan “house” → zadîn “houses” → zadîna “houses (subjective)” (SD/430).
• azra “sea” → azrî “seas” → azrîya “seas (subjective)” (SD/247, 431).

Gendered Subjective Plurals: Gendered plurals in the subjective add the gendered plural subjective suffix -im to the plural form.

• banâth “wife” → †banîth “wives” (archaic strong plural) → †banîthim “wives (archaic subjective plural)” (SD/430).

By the time of Classical Adûnaic, most of these plurals ends in a vowel, and the suffix -im combines with the final vowel according to the Adûnaic rules for vowel-combinations. In all such cases, the i in the suffix is absorbed by the preceding long vowel or diphthong, effectively reducing the suffix to -m:

• bâr “lord” → bârî “lords” → bârîm “lords (subjective)” (SD/430).
• nardû “soldier” → nardûwî “soldiers” → nardûwîm “soldiers (subjective)” (SD/430).
• #Adûnâ “Númenórean” → Adûnâi “Númenóreans” → Adûnâim “Númenóreans (subjective)” (SD/240, PE17/18).
• Avalô “Power, God” → Avalôi “Powers, Gods” → Avalôim “Powers, Gods (subjective)” (SD/241).
• izrê “sweetheart” → izrê “sweethearts” → izrêm “sweethearts (subjective)” (SD/438).

The last example (izrê) has another plural form. As noted above, plurals of nouns ending in -ê (and perhaps also those ending in -î) can use a linking-consonant n to help distinguish the singular and plural forms. In such cases, the gendered plural subjective suffix -im is added to this variant plural form with the linking n:

• izrê “sweetheart” → izrênî “sweethearts” → izrênîm “sweethearts (subjective)” (SD/438).

Gendered Subjective Plurals with Syncope: The gendered strong-I nouns (those ending in a consonant preceded by a short vowel) are an exception to the above rules. Such nouns first undergo the Adûnaic syncope before the subjective suffix -im is added, so that the last short vowel of the noun is lost instead of being replaced by the plural inflection î:

• Nimir “Elf” → Nimrim “Elves (subjective)” instead of **Nimîrim (SD/436).
• tamar “smith” → tamrim “smiths (subjective)” instead of **tamîrim (SD/436).

Where the syncope cannot occur, the subjective suffix -im is added to the normal plural form, as above:

• #Êruhin “Child of God” → Êruhîn “Children of God” (SD/311) → Êruhînim “Children of God (subjective)” (SD/247).

Irregular Plurals

There are several attested Adûnaic plurals that do not fit the plural formation rules described above.

Strong plurals with medial y: For strong nouns that have an isolated medial y, this y disappears when the last vowel is replaced by the plural inflection -î-, so that the plural inflection forms a diphthong with the second-to-last vowel:

• zâyan “land” → zâin “lands” (SD/423, 435).

This irregularity can be explained by the ancient phonetic development of Adûnaic, in which medial [w] and [j] vanished before [u] and [i].

• ✶zāyan → (plural) ✶zāyīn > zā-īn > zâin (SD/423).

Variant plurals with short i: In a few places, Tolkien has plurals with a short i where a long î would be expected from the rules above:

• bâr “lord” → bâri “lords” (SD/251).
• bâr “lord” → bârim “lords (subjective)” (SD/247).

In Lowdham’s Report, these examples appear as regular plurals with a long î:

• bâr “lord” → bârî “lords” (SD/438).
• bâr “lord” → bârîm “lords (subjective)” (SD/438).

These variations may be remnants of Tolkien’s older conception of the Adûnaic plural, which frequently used a short i instead of a long one (see the entry on the draft-plural).