This hypothetical rule is needed to explain ᴹ✶ulgundō > ulgund > ulgon > Ilk. ulion (Ety/ÚLUG), as noted by Helge Fauskanger (AL-Ilkorin/ulgund). A similar development occurred in Noldorin, and it is likely the Ilkorin development followed the same process, with [g] first becoming [ɣ] or [j] and then developing in the vowel [i]. The only example of this rule indicates that the change was quite late, so it is difficult to reconcile with other similar Ilkorin changes for [ɣ] (= “gh” or “ʒ”) and [j] (= “y”).

In the Falathrin dialect, this change also seems to have occurred for [g] between [r] and a vowel: compare Ilk. Argador to Fal. Ariador (Ety/GATH(H), AR²).