Is talking to yourself really a sign of madness?

No, it is a way to dispel loneliness. 40% to 50% of the people talk to themselves audibly; some do it quietly. So, it is normal. Psychologists determined that it is a normal thing decades ago. It could also be a way to sort things out, on your own. 

I saw somewhere that it gives you self-therapy. It's actually good for you.
“Talking to ourselves is completely within the norm. In fact, we talk to ourselves constantly,” says Dr. Jessica Nicolosi, a clinical psychologist based in New York. “One can argue that just thinking things through quietly, without speaking out loud, is talking to ourselves.”

No, we all do it at one time or another. 

At one time it was.  Now it is a sign that they are on the phone.

Actually I find that if I read something out loud, it is easier to grasp the meaning.  I suppose some people talk themselves through things the same way

No way. I live on my own and talk to myself all the time (tho I have to be careful to keep that in check when I'm out shopping!) 

only if you start talking to someone who isnt there.

No.  Answering yourself, however, IS trouble.

No, it's a sign that you have acknowledged the fact that there typically is no intelligent life around you that is capable of carrying on a conversation about anything.

No,too many people do it and it's a way
to get things off your mind.

According to psychiatrists everything you do is a sign of “madness” and they have a diagnosis and neurotoxic drug for that. So why would you let somebody else be your authority when it comes to living your own life? If you’re talking to yourself,  who else are you REALLY harming by doing that?

 It’s all backwards. If you talk to yourself you’re “mad”? But the psychiatrists who unnecessarily prescribe the drugs that destroy people’s lives and even cause them to kill themselves because of the side effects are “sane”? Tell me more. LOL.

Down the rabbit hole we go....