There are two examples indicating that Ilkorin [d] spirantalized after [r]. The simplest example is ᴹ✶eredē > Ilk. erdh [erð], where the [r] and [d] came into contact after the middle [e] was lost due to the Ilkorin syncope, as suggested by Helge Fauskanger (AL-Ilkorin/erdh).

A more complex example is Dor. garth, whose cognates N. ardh and ᴹQ. arda imply a primitive form of [ɣarda] or [garda] (Ety/ƷAR). This means that the [d] would first have become [ð] after the [r], and then after the vowel was lost the final [ð] became [θ] (= “th”). This change is more clearly indicated by the deleted Doriathrin form: garth (dh) (EtyAC/ƷARA). Helge Fauskanger originally suggested this development (AL-Doriathrin/garth).

In Noldorin, all voiced stops became spirants after liquids [l] and [r], but that does not seem to be the case in Ilkorin. Except for [rd], there are plenty of examples of voiced stops followed a liquid: [rg] in targ, [lg] in olg, [ld] in (n)gold and [lb] in galbreth.