My son has an emphatic, “No.” It starts high and moves down but maintains a full volume throughout. The effect is clearly, “What a crazy idea that you have just proposed, and thanks for never wasting my time with it or anything like it ever again.” He has worn that word out for everyone but, apparently, himself.
Just a few days ago, he finally figured out the yes word. His yes includes that hard to pronounce s. It is very clear and even a little elongated. Yess. Not a snake hissing or evil villain, but very clear. He will even correct my yeah to a yes. He genuinely seems to take pleasure in saying the word. It comes with a smile. I am not sure he could ever wear out this new-found word.