Adjectives

(a)unvoiced, voiceless, surd, hardproduced without vibration of the vocal cords“unvoiced consonants such as `p' and `k' and `s'”
(a)disenfranchised, disfranchised, voiceless, votelessdeprived of the rights of citizenship especially the right to vote“labor was voiceless”, “disenfrenchised masses took to the streets”
(s)breathed, voicelessuttered without voice“could hardly hear her breathed plea, `Help me'”, “voiceless whispers”
(s)aphonic, voicelessbeing without sound through injury or illness and thus incapable of all but whispered speech