The Ilkorin genitive suffix (Ety/NAUK), attested in Dor. Tor Tinduma “King of Twilight” (Ety/TIN). It might have developed from the root ᴹ√NĀ/ANA, which is the source of the Quenya genitive suffix ᴹQ. -n and the Noldorin preposition N. na “of”. Helge Fauskanger suggested instead that it developed from a suffixal form of ᴹ✶ʒō (AL-Ilkorin/-a). This second derivation seems more plausible given its plural form -ion, though the plural could also have developed from (plural) ✶ī + (genitive) ✶āna > ✱✶-iān(a) > -iōn > -ion. See the entry on the genitive inflection for further discussion.
Conceptual Development: This suffix and its plural are the same as the Gnomish genitive suffix -a with plural -ion (GG/10). The derivation of the Gnomish genitive is closer to Mr. Fauskanger’s suggested etymology of the Ilkorin genitive, giving further support to his theory.