You run into and read about people who say they have heard the voice of God. I have never heard of two people, or a room full of people, who all heard the same god say the same thing. From that alone the logical conclusion is the voice is coming from inside the person, not from anywhere else.
I would imagine if you queried enough people judged to be of sound mind you would find many who have seen and heard voices other than that of God. We all have dreams where others appear. Maybe voices while awake are similar.
The link tells of a conversation with a musician who saw and heard the voice of a fox. The man and said the fox experience was as beautiful as falling in love with a woman.
This experience had been preceded by an intense interest in and observation of foxes. But, after becoming preoccupied with other things, he now seldom has this encounter. He had to maintain a mental awareness of and focus on the fox to hear it.
It could be that people are simply hard wired to hear things and interpret beyond what is in front of them. Maybe this trait helped the ancients to hear what they thought was danger and move in the other direction and survive. Those without this ability did not.
Hearing the voice of the god or anything else is not bad, except when you expect others to hear it also. It’s not there for others.