In defense of my statement that yes is a noun LOL
I majored in languages in college and took advanced placement english in hs. But I learned this in jr high!
a noun is a person place or thing. When Yes is used in a sentence such as "We need a yes or a no" then yes is a noun. When it is not in a sentence as the noun it is used as an adverb. I just didnt' clarify when I called it a noun.
Yes (no pun intended) it is commonly used as an adverb.