Before I go on, allow me to ask you some questions. Do you have voices in your head? When you read, is there a voice reading the words? When you have a thought, is that thought voiced in your head? Is it your voice or someone else?
Thought is a strange thing indeed. A thought can be like an idea, memory, opinion, belief, a picture or sound, even a feeling or other senses, and sometimes something completely indescribable.