It could mean to talk fluently, or with a pleasing voice like you would hear on the radio with an announcer. It "could" mean somebody like a politician who speaks in ways to avoid getting himself in trouble or avoiding sensitive issues. But that is usually referred to as a "smooth talker"

It means "speak fluently". It could also mean "speak convincingly and tactfully" (this often implies deception).

It Indicates " To Speak Politely "