Voice
One's voice was sound that enabled speech.
A Time Lord's voice changed during their regeneration. When the War Master regenerated, Martha Jones recognised the voice of his successor, knowing him as Harold Saxon. (TV: Utopia) During the Planetary Relocation Incident, Davros noted that while the Tenth Doctor's voice was different, its arrogance was unchanged. (TV: The Stolen Earth)
The Greys of the Church of the Outsiders had voice-changers implanted into their bodies. (AUDIO: Believe)
Voices could be used to access restricted areas. Nicolas Frumkin had access to part of the PhiCorp building in Los Angeles. Jack Harkness and Gwen Cooper recorded his voice to grant them access. (TV: Escape to LA)
After Giles repaired Box, it took on Liz Shaw's voice. (HOMEVID: When to Die)
Mark VI combat mechanicals were capable of analysing voices. (PROSE: The Secret in Vault 13)
During the Battle of Canary Wharf, the Tenth Doctor believed that the Daleks' high-pitched screaming voices were the result of the Dalek mutants being stuck in their casings and unable to feel or touch anything. (TV: Doomsday)
Raxacoricofallapatorian skin suits masked the true voice of their users, making them sound human. (TV: Aliens of London / World War Three)