Maybe a symptom, not necessarily a disorder.
No, it is done by many. I do it but I say that I am talking to my cat.
It depends what kind of talking. Generally, if you are aware these are your own thoughts (i.e. you don't have a thought disorder and think someone is planting them in your head), you do not have a mental illness. This is actually quite normal, and some people even talk to themselves out loud.
yes you will be a freak! It would become a problem if you talk to someone else who is not there (ie an imaginary person), or if it is a constant need to talk if no-one is around. Try putting a radio on if you need "noise" around you. Not at all! Very many sane people (including myself) sometimes need to think aloud to clarify our thoughts. This is NOT a sign of insanity, unless maybe it is excessive and excludes normal conversation.
they are loud
Yuu can complain by: whining, talking out loud, or talking in your head.
Talking to yourself doesn't mean you're insane. Some people talk to themselves when faced with a difficult problem and they think better out loud. But if you talk to yourself and someone else answers, you might want to see a therapist, because that can be troubling.
is it the way you are talking .eg how loud
Silent reading is reading without pronouncing words out loud. It is reading to oneself.
43 dB is not so loud, when you don't want to sleep.
Out loud, versus reading or some other activity to yourself, where you don't say it out loud.
Sing in a microphone and amplify that.
Figure it out yourself
A 'schizophrenic' -person with schizophrenia (mental disease). The person hears non existing voices and has hallucinations, to which they respond by talking out loud