Demonstrative, Relative, and Correlative Stems (DRC) from 1948 had a set of neuter/abstract pronominal forms for the “other [thing]”. A rejected draft of the pronominal section first had {arya} “something else” (PE23/103 note #40). In the revised page Tolkien first gave apa, apana “another matter; quite a different matter”, revised to assa, astana and finally aiana, aina, with the gloss revised to “anything else; some other matter; a different matter” (PE23/104 and note #54). In this document, the neuter pronouns referred only to abstract facts; for concrete objects the personal pronoun ᴹQ. aiane was used.

DRC also had a set of adjective forms that underwent similar changes (PE23/105 and note #68). Tolkien first had apa, apana “other, quite different”. Tolkien revised this into two separate adjective forms warya “other, different” and warya, warimma “any other”. The first adjective was revised to asta, aia, then asta was deleted. The second adjective became aiana and its gloss was changed to “alien, strange, any other”, with a hard-to-read variant astana that was deleted. Later in the same document Tolkien had {arima or estima “of other kind” (PE23/106 note #80) >> warya, warima “of other sort” >>} aiana (aia) “of another sort, other” and aianima “of other sort” PE23/107 and note #89).

The full development seems to be {arya >> apa(na) >> warya >> assa, asta(na) >>} aia(na) used as both adjectives and (neuter/abstact) pronouns, with {arima/estima >> warimma >>} ᴹQ. aianima meaning “of other sort” (see that entry for details).

See the entry ᴹQ. aia(na) for references to the adjective forms from DRC. See the entry Q. hyana for a discussion of adjective forms in other conceptual periods with similar meaning.