Eldamo : Adûnaic : spirant [x] became breath [h] except before [s] and for double [xx]

Ad. spirant [x] became breath [h] except before [s] and for double [xx]; [x{!sx}|-x] > [hX|-h]

Ad. spirant [x] became breath [h] except before [s] and for double [xx]; [x{!sx}|-x] > [hX|-h]

The Primitive Adûnaic spirant ✶[x] (which Tolkien spelled “H”) in most cases developed into a “breath-H” [h] (SD/419). It was retained before [s] and as a double-consonant [xx]. Given that the aspirate [kʰ] did not also develop into [h], this change must have happened before aspirates became voiceless spirants ([kʰ] > [x]).

Elsewhere Tolkien indicated that the changes in [ɣ] happened in “parallel with the softening of the voiceless equivalent H [x] to the breath-H” (SD/420), putting all of these change roughly at the same stage of development.

References ✧ SD/419-420

Order (01000)

After	00200	[ŋx] became [xx]
Before	01200	aspirates became voiceless spirants

✶Ad. 3 [changed in] parallel with spirant [x] became breath [h] except before [s] and for double [xx] ✧ SD/420

Phonetic Rule Elements

[x{!sx}|-x]

[hX|-h]

✧ SD/418 (H > H); SD/419 (H > H)