talking out loud

Ever hear someone say he was "just thinking out loud"? That phrase makes sense to me, but I keep hearing people say they're "talking out loud." Well duh. How likely is it that you wouldn't be talking about loud? And if you have to explain to someone why you're saying what you're saying, it is very likely that you're saying it aloud.

A character in a comic book used to say "talking out loud" all the time. I kept waiting for someone to tell the author that he got it wrong, and then another character would have to explain it to the character who always said it.