aphonia
noun
apho·nia (ˌ)ā-ˈfō-nē-ə 
: loss of voice and of all but whispered speech
aphonic
(ˌ)ā-ˈfä-nik -ˈfō-
adjective -ˈfō- 
Word History
Etymology
borrowed from New Latin aphōnia, borrowed from Greek aphōnía "speechlessness, mispronunciation," from áphōnos "voiceless, mute" (from a- a- entry 2 + -phōnos, adjective derivative of phōnḗ "voice, speech") + -ia -ia entry 1 — more at phono-
First Known Use
1654, in the meaning defined above
Medical Definition
aphonia
noun
apho·nia (ˈ)ā-ˈfō-nē-ə
: loss of voice and of all but whispered speech