What is a voice in your head?

A voice in your head is an auditory experience that originates in your own head, but does not seem to be merely your own thought.  It differs from an attitude, because it is an auditory experience.

If a voice in your head argues with you, or in any other way appears to have a mind of its own, it may be the voice of an alternate personality, which, in most cases, is creative (like the character of a fiction writer) and not a mental illness.