Why is "duh" the word chosen to represent ignorance? Merriam Webster defines "duh" as "used derisively to indicate that something just stated is all too obvious or self-evident." But a derivation isn't given. Why "duh"?
I've checked out the answers to the previous duh question, and I get no satisfaction. The Wikipedia entry on the universality of "mama" and "papa" provides an analogy.
Why do babies first say "mama" and "papa?"
"These terms are built up from speech sounds that are easiest to produce (bilabials like m, p, and b and the open vowel a." https://en.wikipedia.org/wiki/Mama_and_papa
The babies, of course, initially have no idea that these sounds mean mother and father, but the reaction of the mother and father will attach the meaning to those sounds. Is "duh" a variation on "uh?" Is "uh" a sound that a human might first utter when in need? Open-mouthed. Simply formed. A grunt really. Food! Food! But someone who has to beg for food may be flawed. Too stupid to find their own food.