unvoicing

The long Paiute word that we have analyzed is marked as a rigid phonetic unit by several features, chief of which are the accent on its second syllable (wií - “knife”) and the slurring (“unvoicing, ” to use the technical phonetic term) of its final vowel (- mü, animate plural).

Chapter 2. The Elements of Speech 1921

Yet this final l with its latent tendency to unvoicing might never have actually developed into a fully voiceless l had not the presence of voiceless l-sounds in A acted as an unconscious stimulus or suggestive push toward a more radical change in the line of B’s own drift.

Chapter 9. How Languages Influence Each Other 1921