devocalize or devocalise /dē-vōˈkə-līz/ or devoice /dē-voisˈ/

To make voiceless

• spiral bound
• spiraled
• spiral fracture
• spiral fractures
• spiral galaxies
• spiral galaxy
• spiraliform
• spiralism
• spiralisms
• spiralist
• spiralists
• spiralities
• spirality
• spiralled
• spiralling
• spirally
• spiral ratchet screwdriver
• spiral ratchet screwdrivers
• spirals
• spiral staircase
• spiral staircases
• spirant
• spirants
• spiraster
• spirasters