This Primitive Adûnaic phoneme was a spirant in the k-series (velars) described as the “corresponding voiced spirant or ‘open’ G” (SD/417). Very probably it was the voiced velar fricative which Tolkien generally represented with the symbol “ʒ” (IPA [ɣ]). This sound did not survive into Classical Adûnaic, vanishing in most cases.

When [ɣ] appeared initially, finally, between vowels or before another consonant, it vanished. Between vowels, the removal of this sound often resulted in a diphthong or a combined (lengthened) vowel: ✶[aɣa] > [ā] (SD/420). When final or before a consonant, the preceding adjacent vowel was lengthened after [ɣ] vanished: ✶[-aɣ] > [-ā] or ✶[aɣda] > [āda]. As an exception to these rules, [ɣ] became [w], [j] between [u], [i] and another vowel instead of vanishing (SD/420).

When [ɣ] appeared after another consonant, it changed its sound instead of vanishing. When appearing after voiced consonants, [ɣ] assimilated to preceding voiced consonants resulting in a double consonant, whereas [ɣ] became [h] after voiceless consonants (SD/422).

It is not clear what would have happened to double ✶[ɣɣ] from the phonetic rules given by Tolkien. This is unfortunate, because it would be a useful clue in figuring out the ordering of various phonetic changes. The assumption here is that the first [ɣ] vanished while lengthening the preceding vowel, then the second [ɣ] also vanished, though it is conceivable that the second [ɣ] became [w], [j] between [u], [i] and another vowel.

Tolkien represented this sound with the symbol “3” in the typescript of Lowdham’s Report, but elsewhere he usually used the symbol “ʒ” for this sound. He probably only used a “3” because he was working on a typewriter. This discussion of Adûnaic here uses the symbol “ʒ” to represent [ɣ] orthographically.