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”, “disenfranchised 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