It may have been the last 10,000 years that writing was developed. Yet, speech, talking, spoken language is much older. Whether speaking or writing, the subject of "voice" often comes up. With speaking, we can hear the pitch of the voice, a high note or a low one. In Western opera, the tenor is often the lover, maybe because a younger man will often not have developed the gravely, very deep voice of an older man. With writing, by "voice", what is being referred to is often the personality and maybe the character of the speaker, narrator or source of the written words. If an actor delivers all of his lines from the side of his mouth, as though he wants to hide that he is speaking and remained mostly unnoticed, the audience understands that he is not seeking the limelight. He may be a person sought by the authorities. He may be unreliable or dangerous or both.
Voice, manner and speed of speaking, choice of words ["We found a body" vs. "We came to a bloody, stinking smear of a body"] all add up to information and impression, much like what we get by looking at the face, the gait and gestures, the posture. Some people say that a person's scent has an important effect on whether one likes that person or not. I don't usually have a feeling of reaction to a person's scent but the speaking voice is different. Just as a tune played on a trumpet, a flute or a guitar will strike me differently, so a person's speaking voice seems to affect how I feel about the speaker.
Just hearing a voice for the first time is different from hearing that same person speaking many times a year for years and years. I am impressed with how few words a person can speak on the phone before I recognize who is talking.
