Have you ever tried meditating? The first time you do you probably think your mind isn't wandering, it actually takes a bit of practice to even notice quite how much internal dialogue you actually have. It's non stop for most of us.
I am at around stage 3 just now.... Nowhere near enough to stop my thoughts but they are definitely calmer.
Have you ever had an idea or thought, and found it initially impossible to find the right words and phrases to express it? I certainly have. babies with no language can identify objects and people, develop emotional connections, learn skills and solve problems long before they can speak. Are they not concious?