You have a voice when you breathe out and your vocal chords vibrate, producing sound, and eventually speech. People have different tones of voice. With a voice you can sing, speak, yell, whine, or hum.

the sounds a person can make

You have a voice when you breathe out and your vocal chords vibrate, producing sound, and eventually speech. People have different tones of voice. With a voice you can sing, speak, yell, whine, or hum.

Communicating by phone. More intimate than texting but less so than speaking in person, or "face to face."

The voices in your head that tell you to do things.

A voice channel in a VOIP application such as Discord, Teamspeak etc.

A term that Alan Rickman fans use to refer to him. Rickman, known most famously for his role as Professor Snape in the Harry Potter movies, posesses a voice that has been described variously as: melancholy, seductive, disdainful, languid, honeyed, and velvet baritone.
This nickname is also reinforced by Rickman having played the role of Metatron in the movie "Dogma". Metatron was known as "The Voice of God."