Is there a zen/buddhist reason why people go "Uhhhh" or "HMMMmmm!" when they're thinking outloud?

Does it have something to do with it changing one's state of mind to think of a solution faster, or a way to expand the mind's critical and abstract thinking ability to think of a wider variety of solutions if no solutions are found in the more limited approach of arriving to a solution? Do monks practice saying "Ommmm" at a specific frequency and amplitude to stimulate certain brainwave frequencies to reach a certain state of mind, and our ancestors evolved over millions of years to utter a drone sound to do that, and society basically conditions us into thinking that the natural occurring droning sound is really just a symptom of stupidity and slow thinking and has no relation to something much deeper?