In the Ilkorin phonetic developments described in The Etymologies, it appears that an initial palatalized velar became a non-palatalized dental, as noted by Helge Fauskanger (AL-Ilkorin/telf), similar to the medial development of labialized velars described in the Comparative Tables (PE19/23). There are two examples: Ilk. Dilion derived from the root ᴹ√GYEL (Ety/GYEL) and Ilk. telf derived from the root ᴹ√KYELEP (Ety/KYELEP). It seems likely the rule applied to other initial labialized velars as well.

Conceptual Development: This rule contradicts the initial developments described in the Comparative Tables, where [j] was lost after initial velars (PE19/18-20). It seems that Tolkien changed his mind between writing the tables and beginning work on The Etymologies. In some later tables on “Belariandric”, it seems Tolkien toyed with restoring this development (PE18/105): gy > g (not d), but he soon after abandoned the Ilkorin language completely.

In the Ilkorin phonetic developments described in the Comparative Tables, initial labialized velar lost their labialization but remained velars (PE19/18-20), and similarly for dentals (PE19/22). This change is not attested in The Etymologies, where it seems that initial palatalized velars became dentals.