The first of two rules in which the sound of ✶[ɣ] changed after another consonant. Tolkien stated that “after voiced sounds it [ɣ] was assimilated to these” (SD/421). He gives four examples of this rule in Lowdham’s Report: M3 [mɣ] to MM, 93 [ŋɣ] to 99 [ŋŋ], B3 [bɣ] to BB and D3 [dɣ] to DD (SD/421-2).

The complete list of primitive voiced consonants is [b], [d], [g], [w], [l], [r], [z], [j], [m], [n], [ŋ] (excluding palatals and [ʔ], which changed or disappeared early). Of these, this rule definitely did not apply to [n], because [n] assimilated in position to following consonants, so that ✶[nɣ] would have already become [ŋɣ]. This rule may or may not have applied to [w] and [j], depending on when w/y-vocalization (where [w] and [j] became [u] and [i] before consonants and finally) occurred. If w/y-vocalization happened first, then this ɣ-assimilation rule applies only to [b], [d], [g], [l], [r], [z], [m], [ŋ].