unvoiced, voiceless, surd, hard -- (produced without vibration of the vocal cords; "unvoiced consonants such as `p' and `k' and `s'")
unexpressed, unsaid, unstated, unuttered, unverbalized, unverbalised, unvoiced, unspoken -- (not made explicit; "the unexpressed terms of the agreement"; "things left unsaid"; "some kind of unspoken agreement"; "his action is clear but his reason remains unstated")
(TTS Sound)
