it sounds like hypnagogia. i get this thing (quite frequently) where, as i'm falling asleep, i could be thinking of some random-ass scene in the "background" i guess like a classroom, and then suddenly a noise like a binder falling on the floor actually produces an audible sound. it could be a similar effect, and it's a normal thing. startling, and a bit weird, but normal.
you hear your thoughts in your dreams anyway, but sometimes dream stuff seeps into your awake state. often times when i'm falling asleep, i could be thinking of random things like car headlights or lightning, and as the car headlights pass behind trees or the lightning strikes the ground in the distance, i can actually see the light of them. of course, i usually have to be near sleep for this to occur, but the back of my eyelids is dark so the sudden bursts of light startle me awake again.
the brain is weird bro but if you start experiencing these things outside of bedtime, consult a psychiatrist and get a mental health examination done.
